Full opinion text
OPINION CLAY, Circuit Judge. Defendants Chris Young (“Young”), Demetrius Duncan (“Duncan”), Alto Parnell (“Parnell”), and Brian Vance (“Vance”) (collectively, “Defendants”) appeal their convictions and sentences (collectively, “judgments”) entered by the United States District Court for the Middle District of Tennessee for conspiracy, inter alia, to distribute and possess with intent to distribute 500 grams or more of cocaine and 280 grams or more of cocaine base. The district court sentenced Vance to 200-months’ imprisonment, and sentenced Young and Parnell each to two concurrent terms of mandatory life imprisonment without the possibility of parole, and Duncan to mandatory life imprisonment without the possibility of parole. For the reasons that follow, we AFFIRM the district court’s judgments for all four Defendants. I. BACKGROUND This case arises out of a multi-year investigation into a large drug-trafficking organization in Clarksville, Tennessee. The leader of the organization, Robert Porter (“Porter”), distributed large quantities of cocaine to Vance, Young, and others. Vance distributed powder and crack cocaine to Parnell, Duncan, and others, using a stash house in the Summit Heights housing projects and a cookhouse nearby. Parnell and Duncan then sold the cocaine and crack cocaine to Clarksville residents. Federal agents of the Drug Enforcement Agency (“DEA”) obtained wiretap applications and search warrants, which provided the government with enough evidence to arrest twenty-six individuals associated with the drug trafficking organization, including Defendants. Porter was in the process of selling thousands of dollars of cocaine to Young when he was arrested. The morning after Porter’s arrest, agents executed search warrants and seized drugs, guns, cash, and drug paraphernalia from the homes of Duncan, Vance, and others. In total, thirty-six individuals were charged in an indictment. Thirty-three of those individuals pleaded guilty, including Vance, who was sentenced to a below Guidelines term of 200-months’ imprisonment. Duncan, Young, and Parnell went to trial, and were each found guilty of multiple offenses and sentenced to mandatory terms of life imprisonment without parole. Procedural History A. Indictment On January 12, 2011, a grand jury charged Vance, Duncan, Parnell, and Young in a four-count indictment with conspiracy, among other things, to distribute and possess with intent to distribute controlled substances, including 500 grams or more of cocaine and 280 grams or more of cocaine base, otherwise known as crack cocaine, in violation of 21 U.S.C. §§ 841(a)(1) and 846 (Count One). Vance was also charged with possession with intent to distribute crack cocaine, in violation of § 841(a)(1) (Count Two). B. Superseding Indictment On April 17, 2013, a grand jury returned a twenty-two count superseding indictment charging, among other things, Duncan, Parnell, and Young with conspiracy to distribute and possession with intent to distribute 500 grams or more of cocaine and 280 grams or more of cocaine base, in violation of 21 U.S.C. §§ 841(a)(1) and 846, and 18 U.S.C. § 2 (Count One). Vance was also charged with being an accessory after the fact to a Hobbs Act violation and to possession and discharge of a firearm in furtherance of a crime of violence resulting in death, in violation of 18 U.S.C. §§ 1951, 924(c), and 924(j) and 18 U.S.C. §§ 2 and 3 (Count Eight) and conspiracy to commit a Hobbs Act robbery, in violation of 18 U.S.C. §§ 1951 and 2 (Count Nine). Duncan and Parnell were separately charged with possessing cocaine and crack cocaine within 1,000 feet of a public housing authority with intent to distribute, in violation of 21 U.S.C. §§ 841(a)(1) and 860 and 18 U.S.C. § 2 (Count Four). Duncan was individually charged with: possession of cocaine base and marijuana with intent to distribute, in violation of § 841(a)(1) (Count Sixteen); possession of a firearm in furtherance of a drug trafficking offense, in violation of §§ 841(a)(1) and 846 and § 924(c) (Count Seventeen); and being a felon in possession of a firearm, in violation of 18 U.S.C. §§ 922(g)(1) and 924 (Count Eighteen). Young was also charged separately with: attempted possession of cocaine within 1,000 feet of a school with intent to distribute, in violation of §§ 841(a)(1), 846, and 860 (Count Eleven); possession of a firearm in furtherance of a drug trafficking offense, in violation of §§ 841(a)(1) and 846 and § 924(c) (Count Twelve); and being a felon in possession of a firearm, in violation of §§ 922(g)(1) and 924 (Count Thirteen). C. Vance Pleads Guilty to Remaining Charges Vance pleaded guilty to the conspiracy and possession charges on April 15, 2013. On June 10, 2013, Vance pleaded guilty to both Hobbs Act counts, and on September 16, 2013, the district court sentenced Vance to a 200-month term of imprisonment and a five year term of supervised release. D. Trial and Sentencing On August 6, 2013, trial commenced on the remaining counts for Young, Duncan, and Parnell. The government provided evidence in the form of testimony from five co-conspirators and a witness to a warranted search of Duncan’s residence, testimony from law enforcement agents, more than two hundred intercepted phone conversations between co-conspirators, surveillance footage, and evidence seized during the warranted searches and arrests. The jury convicted Duncan, Parnell, and Young on all counts, except for Duncan, who was acquitted on Count Four. On September 28, 2014, the district court sentenced Young to concurrent mandatory terms of life imprisonment on the drug-related offenses (Counts One and Eleven). On November 24, 2014, the district court sentenced Parnell to concurrent mandatory terms of life imprisonment on Counts One and Four. On April 27, 2015, the district court sentenced Duncan to a mandatory term of life imprisonment on Count One. Statement of Facts Robert Porter, the leader of the Vice Lords drug organization, trafficked large amounts of cocaine in Clarksville, Tennessee. Porter obtained the cocaine from suppliers, such as Quinice Cross and Gregory Brooks (“Brooks”). Brooks testified at trial that he supplied Porter with 10 kilograms of cocaine between 2009 and 2010, with each kilogram costing between $30,000 and $35,000. Porter would then supply Vance, Young, and others with cocaine. Donnie Patterson (“Patterson”), a co-conspirator, testified at trial that Porter would supply him with a quarter to half a kilogram of cocaine about twice a week. Patterson also testified that he saw Porter supply Vance with cocaine. Dmitri Johnson (“Johnson”), another co-conspirator, testified that he saw Porter cook powder cocaine into crack cocaine at his home on a regular basis, and that he witnessed Porter supply crack cocaine to Young at least twice. A. Young’s Involvement in the Conspiracy Intercepted telephone conversations between Young and Porter and surveillance footage revealed that Porter had provided Young with tens of thousands of dollars of cocaine for distribution. For instance, on September 12, 2010, Young told Porter that he was “waitin on one more person” and with that he should have “fifty five all together,” or $5,500, for the cocaine that Porter had provided him. (Appendix A GX 98a.) Porter also taught Young how to cook crack cocaine. During a long phone call, on September 18, 2010, Young discussed with Porter his concern that he was not producing all of the crack he could be, due to his inability to properly cook the powder. “I clearly seen when I knocked it down that it was not all that it was supposed to be ... [It] wasn’t nothin but twelve but I’m wonderin like why and how did it be like that.” (Appendix A GX 136a.) Porter then told Young that he was not “trippin ... I still [mess] up too ... so that aint your first time that aint goin to be your last.” (Id.) On December 9, 2010, a federal magistrate judge issued a search warrant. On December 10, 2010, agents executed the warrant for Porter while he was in the middle of selling cocaine to Young at a gas station. Agents located a cell phone inside Porter’s car. They also found bundles of cash, totaling $10,190 underneath where Young was sitting in the vehicle and from his pants pocket. Additionally, the agents uncovered a loaded handgun, as well as a digital scale from the center console of Young’s car. The scale was covered in white residue that later tested positive for cocaine. During trial, Young stipulated that he .unlawfully possessed the loaded gun. Although not directly related to Young’s involvement in the conspiracy, agents recovered 192 grams of cocaine and 159 grams of crack cocaine from the center console of Porter’s vehicle during the arrest. B.Vance’s Involvement Vance, the highest-ranking member of the gang out of the four Defendants in this appeal, sold the cocaine he purchased from Porter to Duncan, Parnell, and others. On December 11, 2010, a search warrant was executed at Vance’s residence, where agents seized $11,000 from a' safe, 90 grams of crack cocaine, marijuana, á holstered and loaded firearm, ammunition, gun cases for the holstered firearm, gun cases for a pistol, and boxes for an assault rifle. Testimony at the trial also revealed that Vance cooked powder cocaine into crack cocaine at the residence of Jevita Banister on Happy Hollow Road. C. Parnell’s Involvement Parnell usually obtained cocaine directly from Vance; however, on August 27, 2010, Vance told Parnell over an intercepted telephone conversation that he obtained his drugs from Porter, and Parnell responded that he had “figured that.” (Appendix A GX 73a.) On various occasions, Vance and Parnell were worried that they and their fellow gang members were on the verge of being caught by the authorities. For instance, on August 6, 2010, Parnell telephoned Vance to warn him about the police “vice truck, the K-9 truck” and how it had pulled someone over on Thompkins Lane. (Appendix A GX 27a.) In another conversation on October 9, 2010, Vance called Parnell to inform him that he could not come over because he was “packed” and “too dirty.” (Appendix A GX 163a.) In that same conversation, Parnell asked Vance how he did, or how he “pull[ed]” last night,” and Vance responded that he “had nothing but a quarter,” and that he “put 21 in and got 19, the shit look like [ ] if you crush it up it look ... real funny, crunchy looking but it jumped though ... and the powder real ■ real hard.” (Id.) On November 20, 2010, Vance and Parnell discussed how law enforcement arrested other members of the conspiracy and how they “almost caught [Parnell] walking out of Toya’s crib [ ] with an ounce of powder on [him].” (Appendix A GX 191a.) Vance and Parnell also discussed enlisting younger individuals to sell the cocaine and crack cocaine for them: “They gotta sell it. They got to.” (Id.) Vance then stated, “[I]f we fall it’s a [w]rap ... [w]hat they gonna do ... without me or you?” (Id.) D. Duncan’s Involvement Duncan usually obtained crack cocaine from Vance in one-ounce quantities (28 grams), which he then sold to others. On October 29, 2010, Duncan called Vance to ask about buying some “whip” because he had “three plays.” (Appendix A GX 175a.) Testimony from law enforcement agents at trial revealed that “whip” stands for crack cocaine, and a “play” is a customer. On November 17,. 2010, Duncan and Vance discussed how much cocaine Duncan had purchased from Vance and then sold to clients, and how much Vance was storing at Duncan’s. (Appendix A GX 187a) (Vance stated to Duncan that “you had nine, you sold one that made eight, and I put three with it, [t]hen I took it, I took four, so theres [sic] seven of that there ... seven whip.”). Duncan obtained cocaine and crack cocaine from other members of the conspiracy. For example, on November 24, 2010, when Duncan asked Vance for nine ounces (255 grams) of cocaine powder to cook into crack cocaine, Vance told him to call Young Money (another co-conspirator). (Appendix A GX 197a). Duncan was also aware that Porter was Vance’s supplier. For instance, on September 7, 2010, Duncan spoke with Vance on the telephone and asked if Porter was still selling cocaine and crack cocaine by the ounce. (Appendix A GX 89a). On December 11, 2010, agents executed a search, pursuant to the search warrant issued December 9, 2010, of Duncan’s home. During the search, agents found a Smith & Wesson .40 caliber handgun, three loaded magazines for the .40 caliber handgun, and a gun holster in Duncan’s bedroom, right near a $902 stack of cash. Duncan stipulated at trial that he was a convicted felon prohibited from possessing a firearm. II. DISCUSSION Defendants raise numerous challenges to their convictions and sentences. Specifically, Duncan argues that the district court erred in denying: (1) his motions to suppress the communications intercepted from Vance’s phone, and the drugs, guns, and cash seized from Duncan’s home pursuant to the search warrant; and (2) his request for an evidentiary hearing pursuant to Franks v. Delaware, 438 U.S. 154, 98 S.Ct. 2674, 57 L.Ed.2d 667 (1978). Parnell argues that the district court erred in admitting: (1) co-conspirator statements; (2) a law enforcement agent’s testimony concerning background evidence about the investigation; (3) cooperating witness testimony about their guilty pleas; (4) evidence of gun crimes committed by co-conspirators and co-defendants; and (5) evidence of other crimes committed in furtherance of the conspiracy. Young, Parnell, and Duncan argue that the district court erred in: (1) admitting a law enforcement agent’s testimony interpreting the wiretapped conversations during trial; (2) failing to give a cautionary jury instruction addressing the dual roles of the testimony given by the case agents; (3) declining to strike 21 U.S.C. § 851 informations; and (4) concluding that the Eighth Amendment does not prohibit a term of life imprisonment for a drug felon convicted of conspiracy to distribute 500 grams or more of cocaine and 280 grams or more of crack cocaine. Finally, Parnell and Vance challenge their respective sentences. A. Motions to Suppress Duncan challenges the district court’s denial of motions to suppress filed by Vance and Duncan with regard to the wiretap for Vance’s phone, which intercepted calls between Vance and Duncan, in addition to subsequent wiretap applications and renewals relying on that wiretap application. 1.Waiver First and foremost, we conclude that Duncan has waived his challenge to the denial of the motions to suppress. Duncan merely cites to the governing rules and relevant case law on Fourth Amendment jurisprudence and wiretap applications, without citations to the record explaining why there was no probable cause. Duncan attempts to provide justification for his perfunctory argument by explaining that the “word limitations of the instant Brief do[ ] not allow for the parsing of the deficiencies in the 16 authorizations at issue in this appeal.” (Duncan Br. 34.) Duncan then points to the “respective motions [to suppress] in the record” for the “particularized analysis relevant to each application.” (Duncan Br. 34.) Federal Rule of Appellate Procedure 28(a)(8)(A) provides that the argument section of an appellate brief must contain “appellant’s contentions and the reasons for them, with citations to the authorities and parts of the record on which the appellant relies.” Fed. R. App. P. 28(a)(8)(A). Here, Duncan cites to the parts in the record where the motions to suppress are located, and also to the part where the district court denied them. However, Duncan does not point to any findings in the record which would demonstrate how the district court erred or why the wiretap application lacked probable cause. See United States v. Meda, 812 F.3d 502, 519 (6th Cir. 2015) (holding argument in brief that was not supported by citation need not be addressed by the court pursuant to Federal Rule of Appellate Procedure 28(a)(8)(A)); see also Dog Pound, LLC v. City of Monroe, Mich., 558 Fed.Appx. 589, 594 (6th Cir. 2014) (holding that appellant waived argument on appeal by failing to “advance a single argument as to why the judgment of the district court ... was in error,” and the “district court’s reasoning [was not] brought into question.”). Even if Duncan did not waive this argu- . ment, his challenge to the denial of the motions to suppress would still fail because the wiretap application established probable cause that surveillance of Vance’s telephone would reveal communications concerning drug trafficking and necessity for the warrant. 2. Standard of Review When reviewing a district court’s decision on a motion to suppress, we review the lower court’s findings of fact for clear error and its conclusions of law de novo. United States v. Lyons, 687 F.3d 754, 762 (6th Cir. 2012) (citing United States v. Howard, 621 F.3d 433, 450 (6th Cir. 2010)). A factual finding is clearly erroneous when the Court, on reviewing the evidence, “is left with the definite and firm conviction that a mistake has been committed.” United States v. Navarro-Camacho, 186 F.3d 701, 705 (6th Cir. 1999) (citation omitted). Whether a search and seizure was reasonable under the Fourth Amendment is a question of law. United States v. Gunter, 551 F.3d 472, 479 (6th Cir. 2009) (citing United States v. Galloway, 316 F.3d 624, 628 (6th Cir. 2003)). Because the district court denied the motions to suppress, we review all evidence in the light most favorable to the government. United States v. Long, 464 F.3d 569, 572 (6th Cir. 2006). 3. Analysis a. Wiretap of Vance’s Phone Duncan first argues (1) that the affidavit in support of the wiretap application failed to establish probable cause, and (2) the wiretaps were not necessary to the investigation because the investigation’s objectives could have been satisfied without resorting to such an extraordinary surveillance technique. In order to conduct electronic surveillance using a wiretap, federal law enforcement officials must secure authorization by making an application containing “a full and complete statement as to whether or not other investigative procedures have been tried and failed or why they reasonably appear to be unlikely to succeed if tried or to be too dangerous.” 18 U.S.C. § 2518(1)(c). This provision, com-' monly referred to as the “needs statement provision,” was designed to insure that wiretapping is not resorted to in a situation where traditional investigative techniques “would suffice to expose the crime.” United States v. Alfano, 838 F.2d 158, 163 (6th Cir. 1988) (citation and internal quotations marks omitted). “[W]hat is needed is to show that wiretaps are not being routinely employed as the initial step in criminal investigation.” Id. (citations and internal quotation marks omitted). A district court has “considerable discretion” in determining whether the requirements of § 2518(1)(c) have been satisfied. United States v. Stewart, 306 F.3d 295, 304 (6th Cir. 2002) (citation and internal quotation marks omitted). i. Probable Cause in Affidavit We hold that the affidavit underlying the wiretap application for Vance’s phone established probable cause that a wiretap of Vance’s phone would lead to evidence relating to the Porter drug trafficking organization. The affiant, Agent Whitsett, noted that he had participated in the investigation of the Porter drug trafficking organization since 2006 and was familiar with the facts and circumstances of the investigation due to his oral and written communications with other DEA agents, other federal, state and local law enforcement agencies, and confidential informants. Agent Whitsett provided information specifically relating to Vance’s telephone, ie., Target Telephone 2 (“TT2”). Agent Whitsett stated that in the course of interceptions of Target Telephone 1 («TT1”), a phone used by known drug trafficker, Donnie Patterson, agents verified that Patterson called TT2 from TT1 after a confidential informant asked Patterson if he had any drugs to sell. Agent Whitsett confirmed that Vance, also known as “Bird,” was using TT2 to talk to Patterson about availability and pricing for controlled substances. (R. 752, Agent Whitsett’s Wiretap Affidavit for Vance’s Telephone, PagelD# 2712-13.) Agent Whitsett also noted that Patterson called Vance on TT2, in which Vance references that he is “in the kitchen.” (Id. at 2714.) Agent Whitsett discussed in the affidavit that “in the kitchen” or “cooking” are code terms for manufacturing crack cocaine, and that Vance’s reference to one of these terms meant that he was in the kitchen making crack cocaine. (Id.) On another phone call, Patterson called Vance and discussed the arrests of fellow drug dealers and Vance’s run from police when he was “loaded,” which means, according to Agent Whitsett, that Vance was carrying controlled substances on his person. (Id. at 2715-19.) In another phone call between Vance and Patterson, Patterson asks Vance for money, and Vance replies that Vance “can get [Patterson] five thousand if [he] need[s] it.” (Id. at 2720-21.) Agent Whit-sett notes that Vance is letting Patterson know that he has large sums of money on him. Agent Whitsett also provides information in the affidavit on prior drug investigations involving Vance for crack cocaine and manufacturing of crack cocaine offenses. Additionally, Agent Whitsett described TT2’s toll analysis which showed an “extreme frequency” of calls to and from TT2 over a short period of time, and contact with telephone numbers associated with other known or suspected controlled substance traffickers. Agent Whitsett described both of these observations as indicators that the phone is being used to traffic controlled substances. ii. Wiretap was Necessary Second, we find that the government met their burden of demonstrating necessity. The government “is not required to prove that every other conceivable method has been tried and failed or that all avenues of investigation have been exhausted.” Alfano, 838 F.2d at 163. We have summarized the “necessity requirement” as follows: All that is required is that the investigators give serious consideration to the non-wiretap techniques prior to applying for wiretap authority and that the court be informed of the reasons for the investigators’ belief that such non-wiretap techniques have been or will likely be inadequate. Id. at 163-64. This is precisely what the government did in this case. Agent Whitsett stated in the wiretap application that the agents used telephone toll records and pen register data as an investigative tool; however, he noted that “[t]his technique ... only will provide agents with a list of numbers called and will not establish the identities of the persons called or the content of the conversations.... Such information is most productive when used in conjunction with intercepted conversations.” (R. 752 at 2732.) Moreover, the affiant noted that “the information gleaned from [these] telephone records alone has not enabled agents to identify additional Target Subjects, i.e., the source(s) of supply, or ascertain the inner-workings of the organization.” (Id.) Additionally, with regard to the use of confidential informants and cooperating co-defendants, Agent Whitsett stated that “[e]ven though confidential sources and cooperating defendants provide valuable information and assistance, [the] [a]ffiant believes that such information is limited and the continued use of confidential sources and or cooperating defendants, even combined with other conventional investigative techniques, would not result in the dismantlement of the [Porter Drug Trafficking Organization] PDTO.” (Id. at 2737.) Agent Whitsett also noted that, with regard to the use of undercover agents as another investigative technique, “[m]embers of large-scale drug trafficking organizations are particularly suspicious of individuals with whom they are not familiar.” (Id.) Agent Whitsett stated that “it is extremely unlikely that an undercover agent could successfully infiltrate [the PDTO]” at such a high level. (Id.) Moreover, the case agent noted that’ they had asked a confidential informant familiar with Vance to assist law enforcement in targeting Vance, but that he was unwilling to do so. (Id.) The affiant also mentioned how Grand Jury subpoenas would reveal the investigation and expose the prosecution before it was necessary to do so, and how physical-undercover surveillance, especially in concentrated residential areas, is often impossible as there is a high risk that the surveillance will be spotted by the Target Subjects. (Id. at 2730-31.) The district court, after holding a hearing on the motion to suppress, found that there was probable cause for authorization of the wiretaps. The court found that there was a substantial basis to conclude that there was an on-going conspiracy that had been in existence for many years, and thus, the “[wire]taps and the reasons therefor[e] are current and not stale.” (R. 2374, Wiretap Hearing, PageID# 12343.) The district court further found that the case agent met the burden of necessity because he demonstrated that “traditional techniques have been considered or employed such as confidential information, physical surveillance, pen registers, toll information, financial investigations, Grand Jury subpoenas, undercover agent and tracking devices,” which “clearly evidence[d] the limitations and the need for wiretap surveillance in order to complete the investigation of the conspiracy.” (R. 2374 at 12345-46.) Duncan argues that the government could have “take[n] down the [ ]PDTO during the time period they were readily using CIs,” but did not do that “in order to stockpile evidence that ultimately lead to the request for wiretaps.” Duncan also argues that the stated wiretap objective was to learn the identity of the leaders and sources, but law enforcement knew the identity of these individuals for years prior to the wiretap, thus, this objective could have been met without resort to wiretapping. We are not persuaded by Duncan’s arguments because the stated objective of the investigation was to dismantle the drug trafficking organization, and wiretapping individuals alleged to be involved in the conspiracy certainly furthered that objective. Thus, we hold that the district court did not err in denying the motion to suppress because the affidavit gave a substantial basis for finding probable cause and necessity. b. Search of Duncan’s Residence Duncan next argues that the district court erred in denying his motion to suppress the evidence obtained from the search of residence because: (1) the search warrant was without probable cause because it relied on communications from the unlawful wiretaps; (2) the affidavit underlying the search warrant possessed no information that drug trafficking occurred at the residence; (3) the affidavit possessed no information that Duncan resided at the residence searched; (4) the affidavit fails to establish any reasonable nexus between drug trafficking and the residence searched; and (5) the affidavit relied on stale information To determine whether probable cause for a search exists, a judge issuing a warrant must “make a practical, commonsense decision whether, given all the circumstances set forth in the affidavit before him, including the ‘veracity’ and ‘basis of knowledge’ of persons supplying hearsay information, there is a fair probability that contraband or evidence of a crime will be found in a particular place.” Illinois v. Gates, 462 U.S. 213, 238-39, 103 S.Ct. 2317, 76 L.Ed.2d 527 (1983). The duty of a reviewing court is to insure that the magistrate judge had a “substantial basis” for concluding that probable cause existed. Id. (citation and internal quotation marks omitted). In order to establish probable cause, there must be a nexus between the place to be searched and the evidence sought. See United States v. Laughton, 409 F.3d 744, 747 (6th Cir. 2005) (citations omitted). We conclude that the issuing judge had a substantial basis for concluding that probable cause for a search existed. As mentioned above, the wiretaps were not unlawful. Thus, evidence obtained pursuant to the intercepted communications can be relied upon by the issuing judge to conclude that probable cause existed for the search of the residence. Numerous wiretapped phone calls between Duncan, Porter, Vance, and other members of the conspiracy demonstrate that Duncan resides at 964 Woody Hills Drive, and used the residence to store cocaine, proceeds from the sale and/or receipt of narcotics trafficking, narcotics trafficking paraphernalia, and firearms. The affidavit identified Duncan as a ranking member of the Vice Lord street gang who supplied cocaine to numerous Vice Lord gang members. The wiretaps identified a number of locations being used to store cocaine and marijuana along with cash from the sale of controlled substances. One of the locations was 964 Woody Hills Drive, Clarksville, Tennessee. GPS on one of Vance’s wiretapped telephones placed Vance at the Woody Hills Drive location when he stated he was at “Whirley’s,” which is a moniker used to refer to Duncan by the members of the conspiracy. For instance, on September 13, 2010, Porter called Duncan and in that phone conversation, Duncan informed Porter that he had $600.00 with which he wished to purchase cocaine from Porter. On October 29, 2010, Duncan called Vance and stated that he had “about three plays,” that Vance had “no whip,” and that Vance would have to “get to it.” (R. 403, Search Warrant Application, PageID# 177-78.) The affiant stated that the term “play” is used by crack cocaine traffickers to describe a customer, the term “whip” réfers to crack cocaine.” (Id.) On November 21, 2010, Vance, using a wiretapped telephone, made a call to Duncan, in which Vance stated that he “left [his] strap over there.” (Id. at 178.) Duncan then responded, “[0]ver at my house?,” to which Vance responded in the affirmative. (Id.) Vance then stated that he was going to take Duncan’s gun that night, and Duncan responded that he did not want Vance to take his gun because he would not stay at his residence without a firearm. The affiant believed that this call showed that both Vance and Duncan are regularly armed with a firearm, that Vance left his firearm at Duncan’s residence, and that Duncan generally has his firearm at that residence. The affidavit also stated that on April 2, 2010, Duncan received a traffic ticket and gave his address as 964 Woody Hills Drive. The affidavit also establishes that electric service at that location is in the name of Mary A. Duncan. When Duncan was arrested on September 21, 2008, he had a tattoo “Mary Ann Duncan” on his back and gave 964 Woody Hills Drive as his address. (Id.) Together, these interceptions, along with others noted in the affidavit, establish probable cause for a search of Duncan’s residence. See United States v. Williams, 644 F.3d 683, 686 (6th Cir. 2008) (“[T]he courts should take a totality of the circumstances approach in their review of the affidavit, and the courts may afford considerable weight to the conclusion of experienced law enforcement officers regarding where evidence of a crime is likely to be found and [the courts are] entitled to draw reasonable inferences about where evidence is likely to be kept, based on the nature of the crime and type of offense.”) (citations and internal quotation marks omitted). In Williams, we joined our sister circuits that have held in “cases involving a variety of suspected crimes, that an issuing judge may infer that a criminal suspect keeps the ‘instrumentalities and fruits’ of his crime in his residence.” 544 F.3d at 688 (collecting cases). Here, it was reasonable for the issuing judge to infer that a ranking member of a criminal enterprise kept money, guns, and drugs at his residence. Therefore, we find that the district court did not err in denying the motion to suppress the fruits of the search of Duncan’s residence. In addition, the warrant did not rely on stale evidence because the conspiracy at issue was ongoing and the place to be searched was a secure operations base for the conspiracy. See United States v. Spikes, 158 F.3d 913, 923 (6th Cir. 1998) (citing W. LaFave, Search and Seizure § 3.7 (3d ed. 1996) (noting as a general matter that stale information cannot be used in a probable cause determination)). The staleness probe depends on the “inherent nature of the crime.” Id. (quoting United States v. Henson, 848 F.2d 1374, 1382 (6th Cir. 1988)). We must inquire into whether information in the affidavit that is arguably three to six weeks old is stale. Cf. United States v. Frechette, 583 F.3d 374, 378 (6th Cir. 2009) (noting that information that is sixteen-months old in the drug trade is usually stale because drugs are sold and consumed in a prompt fashion). In analyzing whether information, is stale, this Court considers the following factors: (1) the character of the crime (chance encounter in the night or regenerating conspiracy?), (2) the criminal (nomadic or entrenched?), (3) the thing to be seized (perishable and easily transferable or of enduring utility to its holder?), and (4) the place to be searched (mere criminal forum of convenience or secure operational base?). Frechette, 583 F.3d at 378 (citing United States v. Abboud, 438 F.3d 554, 572-73 (6th Cir. 2006) (citation omitted)). See also United States v. Kennedy, 427 F.3d 1136, 1142 (8th Cir. 2005) (“[I]nformation of an unknown and undetermined vintage relaying the location of mobile, easily concealed, readily consumable; and highly incriminating narcotics could quickly go stale in the absence of information indicating an ongoing and continuing narcotics operation.”) (citations omitted). Specifically, Duncan argues that the affidavit does not establish the 964 Woody Hills residence as a “notorious drug den” because at most, the search warrant provides only “six attempted purchases by Defendant Duncan.” Duncan further avers that five of these attempted purchases occurred during a 37-day period ending on September 13, 2010, and the sixth conversation occurred on October 29, 2010. Duncan argues that this pattern is more indicative of an addict than a drug dealer, and that there is no allegation that Duncan attempted to purchase narcotics within 41 days prior to the submission of the search warrant application on December 9, 2010. We find Duncan’s argument unpersuasive. First, the character of the crime, conspiracy to traffic narcotics, is not a chance encounter in the night. It is a regenerating conspiracy. See Abboud, 438 F.3d at 573; United States v. Greene, 250 F.3d 471, 481 (6th Cir. 2001) (finding information supplied by an informant two years prior to issuance and execution of search warrant was sufficient to defeat claim of staleness due to ongoing nature of illegal activity because informant had purchased narcotics at least twelve times at defendant’s house): see also United States v. Canan, 48 F.3d 954, 959 (6th Cir. 1995) (finding ongoing activity at the defendant’s house four years prior to issuance and execution of the search warrant was sufficient to defeat claim of staleness). Second, the affidavit established that Duncan was not nomadic. Indeed, the information in the affidavit indicated that Duncan lived in the Woody Hills residence from at least September 21, 2008, when, upon being arrested, he listed this address as his residence, to November 21, 2010, when he referred to the Woody Hills residence as his house in an intercepted phone call with Vance. Although the warrant was not issued and executed until three weeks after the November 21, 2010 conversation, the information in the affidavit indicated that Duncan lived in the same house for the period leading up to the search. See Abboud, 438 F.3d at 573. Regarding the last two Abboud factors, although generally speaking, narcotics are easily consumable and mobile, narcotics underlying an ongoing conspiracy to traffic drugs are likely to be at an operational base. Thus, the affidavit contained information which established that Duncan purchased and sold narcotics from the Woody Hills residence throughout the period leading up to the search. See Spikes, 158 F.3d at 924 (stating that “the affidavit provide[d] a continuing series of incidents involving either the manufacture, sale, or distribution of crack cocaine that are all connected in one form or another to [defendant’s residence]”.) Indeed, all of the Abboud factors indicate that the evidence was not stale in this case. As discussed in the next section, Duncan argues that the affidavit contained false information because Agent Whitsett did not inform the issuing judge that one of the confidential informants was related to Vance. Even with the inclusion of this information, theré was a substantial basis for the determination of probable cause to search Duncan’s residence. The 187-page affidavit contained information that Duncan illegally possessed a firearm in his home and that he was a drug trafficker for the Porter drug-trafficking organization who. purchased and sold drugs out of his home. Even if Duncan did not waive his argument and even if the district court erred in denying Duncan’s suppression motion, the error was harmless because the evidence presented at trial, separate and apart from the evidence seized from his home, proved beyond a reasonable doubt that Duncan participated in the trafficking conspiracy. The jury listened to Duncan discuss his drug sales and possession of firearms with Vance on intercepted calls, among other pieces of evidence that were presented to the jury. c. Failure to Provide a Franks Hearing Lastly, Duncan argues that the district court erred in denying a Franks hearing because the wiretap applications contained deliberate falsehoods or statements that were made with a reckless disregard for the truth. Duncan briefly mentions in his statement of facts that Agent Whitsett deliberately withheld information and misled' the issuing judge as to the relationship between a confidential informant and Vance, the relationship being that the confidential informant was a relative of Vance. Whether to hold an evidentiary hearing based upon a challenge to the validity of a search warrant’s affidavit, given alleged misstatements and omissions, is committed to the sound discretion of the district court. See United States v. Graham, 275 F.3d 490, 505 (6th Cir. 2001). When reviewing the district court’s denial of a Franks hearing, we review findings of fact for clear error and conclusions of law de novo. United States v. Pirosko, 787 F.3d 358, 369 (6th Cir. 2015) (quoting United States v. Rose, 714 F.3d 362, 369-70 (6th Cir. 2013)). “A defendant is entitled to a Franks hearing if he: 1) makes a substantial preliminary showing that the affiant knowingly and" intentionally, or with reckless disregard for the truth, included a false statement or material omission in the affidavit; and 2) proves that the false statement or material omission is necessary to the probable cause finding in the affidavit.” Pirosko, 787 F.3d at 369 (citations and internal quotation marks omitted). We find that the district court did not err in denying a Franks hearing because the record demonstrates that Duncan did not put forth a strong preliminary showing that Agent Whitsett intended to mislead and exclude critical information from the affidavit. Duncan presented nothing more than an allegation that Agent Whitsett intended to mislead the issuing judge. See United States v. Bennett, 905 F.2d 931, 934 (6th Cir. 1990) (noting that the allegations must be more than conclu-sory and must be accompanied with an offer of proof and supporting affidavits, and if this is satisfied, then the issue becomes whether, absent challenged statements, there remains sufficient content in the affidavit to support a finding of probable cause). Duncan has not met this “heavy burden.” Id. Duncan does not argue why this information was critical to the finding of probable cause. More importantly, there was sufficient content in the affidavit regardless of whether this information was included or not. Accordingly, we conclude that the district court did not err in denying a Franks hearing. Therefore, Duncan waived his arguments challenging the motions to suppress and the denial of the Franks hearing, and even if he had not waived these arguments, the district court did not err in denying the motions to suppress and the Franks hearing. B. Evidentiary Rulings Next, Young, Parnell, and Duncan argue that the district court erred in admitting Agent Whitsett’s testimony which interpreted the wiretapped conversations. Parnell additionally challenges whether the district court erred in admitting: (1) co-conspirator statements; (2) the case agent’s testimony concerning background evidence about the investigation; (3) cooperating witnesses testimony about their guilty 'pleas; (4) evidence of gun crimes committed by co-conspirators and co-defendants; and (5) evidence of other crimes committed in furtherance of the conspiracy- 1. Standard of Review We review a district court’s ev-identiary rulings for an abuse of discretion. United States v. Kilpatrick, 798 F.3d 365, 378 (6th Cir. 2015). In determining whether the district court abused its discretion, the Court “must view the evidence in the light most favorable to the government by maximizing the probative value of the evidence and minimizing its potential preju-. dice.” United States v. Sanders, 95 F.3d 449, 453 (6th Cir. 1996) (citation omitted). The prejudice to be weighed is the “unfair prejudice caused by admission of the evidence. Evidence that is prejudicial only in the sense that it paints the defendant in a bad light is not unfairly prejudicial pursuant to [Federal] Rule [of Evidence] 403.” Id. (citing United States v. Mullins, 22 F.3d 1365, 1373 (6th Cir. 1994)). This Court reviews an evidentiary ruling for plain error if a defendant fails to object at trial. Kilpatrick, 798 F.3d at 378 (citing United States v. Olano, 507 U.S. 725, 731-32,113 S.Ct. 1770,123 L.Ed.2d 508 (1993)). An erroneous evidentiary ruling does not automatically result in a new trial. Id. Evidentiary errors are subject to harmless error review. Id. Under the “harmless error” rule, any “error, defect, irregularity, or variance that does not affect substantial rights must be.disregarded.” Fed. R. Crim. P. 52(a). Non-constitutional errors are subject to the Rule 52(a) harmless error analysis, in which the government must show by a preponderance of the evidence that the error did not materially affect the verdict. Kilpatrick, 798 F.3d at 378. In cases where a non-constitutional error occurred, when the record is “so evenly balanced that a conscientious judge is in grave doubt as to the harmlessness of an error,” the judgment must be reversed. Id. at 379-80 (quoting O’Neal v. McAninch, 513 U.S. 432, 437-38, 115 S.Ct. 992, 130 L.Ed.2d 947 (1995)). When a constitutional error occurs, the government must prove beyond a reasonable doubt that the error did not affect the verdict. United States v. Miner, 774 F.3d 336, 342, 350 (citing Neder v. United States, 527 U.S. 1, 15, 119 S.Ct. 1827, 144 L.Ed.2d 35 (1999)). 2. Agent Whitsett’s Testimony Young, Duncan, and Parnell argue that Agent Whitsett’s testimony was by based on generalized knowledge without any specific foundation, and Agent Whitsett invaded the jury’s province by repeatedly interpreting ordinary English language terms in violation of United States v. Freeman, 730 F.3d 590, 595-99 (6th Cir. 2013). Courts frequently qualify law enforcement officers as expert witnesses under Federal Rule of Evidence 702 to interpret intercepted conversations that use “slang, street language, and the jargon of the illegal drug trade.” Kilpatrick, 798 F.3d at 379 (quoting United States v. Peoples, 250 F.3d 630, 641 (8th Cir. 2001)). Conversely; when a law enforcement officer is not an expert witness, the officer’s lay opinion testimony is admissible “only when the law enforcement officer is a participant in the conversation, has personal knowledge of the facts being related in the conversation, or observed the conversations as they occurred.” Id. (citation and internal quotation marks omitted). Federal Rule of Evidence 701 states that if a witness is not testifying as an expert, “an opinion is limited to one that is: (a) rationally based on the witness’s perception; (b) helpful to clearly understanding the witness’s testimony or to determining a fact in issue; and (c) not based on scientific, technical, or other specialized knowledge within the scope of Rule 702.” Fed. R. Evid. 701. The proponent of this testimony must establish that all three requirements are met. Freeman, 730 F.3d at 595-96. The purpose of lay opinion testimony is to “des-crib[e] something that the jurors could not otherwise experience for themselves by drawing upon the witness’s sensory and experiential observations that were made as a first-hand witness to a particular event.” Id. at 595 (citation and internal quotation marks omitted). a. Interpreting Wiretapped Interceptions Young, Duncan, and Parnell failed to object to most of the challenged testimony. The only testimony Defendants actually objected to was Agent Whitsett’s statement that the term “quarter” could mean a term used by the Vice Lords or a “quarter ounce of crack cocaine.” (R. 1871, Trial Tr. Aug. 8, 2013, PageID# 27-28.) They objected to the inference that “quarter” referred to crack cocaine, and requested a continuing objection “so [they] don’t have to jump up and down every time this happens.” (Id. at 28-29.) The district court overruled the objection to Agent Whit-sett’s testimony about the meaning of “quarter” because Agent Whitsett had two possible interpretations for the phrase and had not determined which of the two meanings he thought was correct. (Id. at 29-30.) The district court further instructed Defendants that if a future objection “is exactly like this one, [they] have got a continuing objection,” but “it may not be. So don’t sit there if [they] have an objection. Go ahead and make it.” (Id.) Young, Duncan, and Parnell were clearly instructed to object to any future testimony that was different than the testimony about the meaning of “quarter.” They did not object as instructed. Therefore, we review for plain error most of Young’s, Duncan’s, and Parnell’s challenges to the agent’s testimony, except for the testimony concerning the meaning of “quarter.” We hold that the district court did not plainly err in admitting Agent Whit-sett’s testimony because, as the district court noted during trial, “[t]here was enough slang and jargon used that [Agent Whitsett’s] testimony as to what they were talking about was necessary and will be helpful to the jury.” (R. 1862, Trial Tr. Aug. 21, 2013, PageID# 169.) In Freeman, a murder-for-hire case in which this Court addressed the extent to which agents may give lay opinion testimony that interprets intercepted conversation, we held that the agent’s testimony interpreting intercepted phone calls was inadmissible under Rule 701 because the agent “repeatedly relied on the general knowledge of the FBI and the investigation as a whole” when offering his interpretations. 730 F.3d at 596. Unlike the agent who testified in Freeman, the agent who testified in this case established a personal knowledge for his testimony. Agent Whitsett testified numerous times to his personal involvement in the investigation since, its inception in 2006, as he was the lead agent on the case by the time the wiretap applications were sought, interviewed witnesses, conducted surveillance, and reviewed thousands of hours of phone calls. (R. 1871 at 22-23 (Agent Whitsett noting that he would come in everyday and try to listen to every call that had been recorded, but at some point that became impossible, so he listened to as many as he could).) Thus, we hold that the district court did not plainly err in admitting Agent Whitsett’s testimony interpreting the wiretapped phone calls. b. Background Information of Investigation Parnell additionally argues that the district court plainly erred by admitting testimony concerning background information about the wiretap and search warrant application process. Parnell concedes that the standard of review is plain error since he did not object to this testimony at trial. We hold that the district court did not plainly err in admitting this testimony. Agents are permitted to testify regarding how they became involved in a case, what allegations they were investigating, who the suspects were, and similar background information. Kilpatrick, 798 F.3d at 381 (citing United States v. Goosby, 523 F.3d 632, 638 (6th Cir. 2008)). “This sort of testimony, which is designed to set the stage for the introduction of evidence, differs substantively from problematic ‘preview testimony’ that ‘purports to sum up (in advance of the evidence) the government’s overall case.’ ” Id. at 381-82 (citation and internal quotation marks omitted). In Kilpatrick, this Court held that the case agent’s testimony concerning the allegations she investigated was proper lay opinion testimony because “[s]he did not offer conclusions or impermissibly argue the government’s case.” Id. at 382. “Explaining the allegations underlying an investigation does not implicate Rule 701 or Freeman.” Id. Specifically, Parnell argues that the prejudicial effect of Agent Whitsett’s testimony concerning background information outweighed its probative value under Rule 403. Parnell cites to an out-of-circuit case, United States v. Cunningham, 462 F.3d 708 (7th Cir. 2006), which held that the district court abused its discretion by admitting testimony relating to the procedures used to obtain wiretap authorizations. The Seventh Circuit reasoned that the government agent’s testimony about the numerous levels of approval required to obtain the wiretap was irrelevant and unfairly prejudicial because the court permitted the jury to infer that the defendant was engaged in illegal activity before the wiretap since a federal judge, the government attorneys, and federal law enforcement had approved it. Id. at 713. However, as the government points out here, the Seventh Circuit has limited Cunningham: the impermissible inference from the type of testimony present in Cunningham is missing when the government places a wiretap on a phone belonging to someone other than the defendant. United States v. Recendiz, 557 F.3d 511, 529 (7th Cir. 2009). “[TJestimony regarding a wiretap on a co-conspirator’s telephone permitted a jury to infer that the co-conspirator was engaged in illegal activity before the wiretap.” Id. (citing United States v. Bustamante, 493 F.3d 879, 888 (7th Cir. 2007)). Here, the wiretap was not placed on Parnell’s phone. The concern in Cunningham, “that the testimony permitted the jury to infer that the defendant was engaged in illegal activity before the wiretap because law enforcement, government attorneys, and a district judge each approved it,” is not present here. Recendiz, 557 F.3d at 529. Rather, the inference that the jury could have drawn from Agent Whitsett’s testimony was that Parnell’s co-conspirators were engaged in illegal activity before the wiretap. See Bustamante, 493 F.3d at 888. Accordingly, we find that the district court did not plainly err in admitting Agent Whitsett’s background information testimony. 3. Co-conspirator Statements Parnell next argues that the district court erred by admitting co-conspirator statements under Federal Rule of Evidence 801(d)(2)(E). Specifically, Parnell contends that the district court erred by not making any factual or legal findings as to whether the requirements under Rule 801(d)(2)(E) were satisfied. “To admit statements of a co-conspirator under Rule 801(d)(2)(E), a trial court must find that: (1) the conspiracy existed; (2) the defendant was a member of the conspiracy; and (3) the co-conspirator made the proffered statements in furtherance of the conspiracy.” United States v. Warman, 578 F.3d 320, 335 (6th Cir. 2009) (citing United States v. Wilson, 168 F.3d 916, 920 (6th Cir. 1999)). This is sometimes referred to as an Enright finding. Id.; see also United States v. Enright, 579 F.2d 980, 986-87 (6th Cir. 1978). The district court may “admit the hearsay statements subject to later demonstration of their admissibility by a preponderance of the evidence.” Warman, 578 F.3d at 335. (citations and ■ internal quotation marks omitted). Whether the government made the necessary showing is a question of fact that this Court reviews for clear error. United States v. Maliszewski, 161 F.3d 992, 1007 (6th Cir. 1998) (citation omitted). This Court reviews the district court’s legal conclusion regarding admissibility de novo. Id. (citing United States v. Carter, 14 F.3d 1150, 1155 (6th Cir. 1994)). First, Parnell appears to have made a general objection to the co-conspirator statements being admitted vis-a-vis Duncan’s objection that the “proof has failed to show that Mr. Duncan was a part of the alleged conspiracy in this case, and that those calls, other than the calls that obviously captured Mr. Duncan, should be stricken from the record.” (R. 1862, Trial Tr. Aug. 21, 2013, PageID# 152; see also R. 1871, Trial Tr. Aug. 8, 2013, PageID# 19 (district court granting motion that an objection by one defendant is an objection by all).) The record indicates that the district court instructed Defendants to object to the statements as the government sought their admission so the court could “have on the record that there are no objections” because that “is the way [the district court] ha[d] been doing it.” (R. 1871, Trial Tr. Aug. 8, 2013, PageID# 19-20). But the record indicates that despite this instruction, Parnell did not object to. the co-conspirator statements as instructed. Moreover, even if the brief reference by Duncan’s counsel preserved Parnell’s objections, it preserved them only to the extent that Parnell argued he was not a member of the conspiracy. Because Parnell challenges all three conspiracy requirements before this Court, the standard of review here is abuse of discretion for Parnell’s challenge to' the finding that he was a member of the conspiracy, and plain error for the finding that a conspiracy existed and that the statements were made in furtherance of the conspiracy. For a defendant “[t]o be found guilty of conspiracy, the government must prove that [the defendant] was aware of the object of the conspiracy and that he voluntarily associated himself with it to further its objectives.” United States v. Gibbs, 182 F.3d 408, 421 (6th Cir. 1999) (quoting United States v. Hodges, 935 F.2d 766, 772 (6th Cir. 1991)). “A buyer/seller relationship alone is not enough to establish participation in the conspiracy, but further evidence indicating knowledge of. and participation in the conspiracy can be enough to link the defendant to the conspiracy.” Gibbs, 182 F.3d at 421-22. We hold that the district court did not abuse its discretion or plainly err in admitting the co-conspirator statements because the record demonstrated that a conspiracy existed, that Parnell was a member of the conspiracy, and that the statements were made in furtherance of the conspiracy. The district court made factual and legal findings concerning Parnell’s membership in the conspiracy in its order denying Parnell’s renewed motion for judgment of acquittal and, in the alternative, motion for new trial. The court found “that there was more than sufficient evidence for a reasonable jury to conclude that Parnell was a member of the conspiracy to distribute drugs in Summit Heights.” (R. 2003, District Court’s Order Den. Parnell’s Mot. for J. of Acquittal, PageID# 11.) The court went through the evidence presented by the government and explained why the evidence suggested that Parnell was a member of the conspiracy and that he had more than a mere buyer-seller relationship with other members of the conspiracy. The record also demonstrates that the district court found that a conspiracy existed. (R. 2003 at 15 (finding evidence showed Parnell and Vance “engaged in a joint venture to cook crack cocaine.”).) The district court also found that the co-conspirator statements were made in furtherance of the conspiracy. (Id. at 10701 (finding conversations with other members of the conspiracy “were not about those individuals’ well-being, but conversations relating to those individuals in the sale and cooking of cocaine, and the yields they obtained.”).) Moreover, it was not abuse of discretion or plain error for the district court to make these findings at the close of the trial, as long as it made such findings. See United States v. Conrad, 507 F.3d 424, 430 (6th Cir. 2007) (finding district court erred in failing to make requisite findings regarding context and timing of co-conspirators’ out-of-court statements before admitting them); United States v. Fisher, 22 F.3d 574, 578 (5th Cir. 1994) (stating that district court may defer its Rule 801(d)(2)(E) findings until close of government’s case but it is error to omit such findings altogether). Moreover, any error or abuse of discretion was harmless because Parnell failed to demonstrate that any error affected his substantial rights. 4. Cooperating Witnesses’ Testimony Parnell further argues that the district court plainly erred in allowing cooperating co-conspirators to testify that they pleaded guilty to offenses in connection with the charged conspiracy when such testimony was elicited on direct examination without a cautionary jury instruction. The government contends that “guilty pleas and convictions may be introduced into evidence if the co-conspirator or co-defendant testifies at trial, so that the factfinder will have appropriate facts on hand to assess the witness’s credibility.” Sanders, 95 F.3d at 454 (citation omitted). We conclude that the district court did not plainly err in allowing this testimony to be presented at trial. The sole case Parnell relies on for this argument, United States v. Austin, 786 F.2d 986, 991-91 (10th Cir. 1986), concerns whether the government can question co-conspirators or co-defendants about one of their principal witnesses’ prior convictions prior to that witness needing to be impeached or rehabilitated. Id. at 991-92. The Tenth Circuit held that “it is the testifying witness’ own prior conviction that is admissible on cross-examination to impeach his credibility or on redirect to rehabilitate him.” Id. at 992. Here, the witnesses were being asked about their own guilty pleas, which this Court permits. See United States v. Francis, 170 F.3d 546, 550 (6th Cir. 1999) (“We have allowed a prosecutor to refer to the plea agreement of a testifying witness .... The prosecutor may elicit testimony about its terms, attack the credibility of the witness because of it and even refer to the plea agreement of a government witness in an attempt to deflect defense counsel’s use of the agreement to attack the witness’s credibility.”). Moreover, Parnell is entirely incorrect in arguing that the district court did not give a proper cautionary instruction. The district court gave the following instruction: You have heard the testimony of witnesses who have plea agreements in which the government has promised him or her that the government may make a recommendation for a lesser sentence and exchange for his or her cooperation. It is permissible for the government to make such a promise. But you should consider such testimony with more caution than the testimony of other witnesses. Consider whether his or her testimony make have been influenced by the government’s promise.... You have heard testimony of Demetrius Johns