Full opinion text
MURPHY, Circuit Judge. Petitioner Dewey George Moore appeals the district court’s denial of federal habeas relief from his Oklahoma first degree murder conviction and death sentence. See 28 U.S.C. § 2254. Petitioner was convicted of first degree murder and kidnaping for the abduction and murder of twelve-year-old Jenipher Gilbert. Respondent cross appeals, challenging the district court’s determination that the Antiterrorism and Effective Death Penalty Act of 1996 does not apply to petitioner’s habeas petition. As grounds for habeas relief, petitioner asserts: (1) he is entitled to discovery and an evidentiary hearing on his allegations that police planted evidence against him; (2) the State’s chief witness, a forensic chemist, falsely testified at trial, depriving petitioner of due process and a fair trial; (3) the trial court erred in dismissing a prospective juror for cause; (4) the prosecutor’s misconduct deprived petitioner of a fair trial; (5) the application of Oklahoma’s “especially heinous, atrocious or cruel” aggravating circumstance was unconstitutional; (6) there was insufficient evidence to support the jury’s finding that the murder was “especially heinous, atrocious or cruel”; (7) Oklahoma’s continuing threat aggravating circumstance is unconstitutionally overbroad; (8) petitioner’s trial and direct appeal attorneys were constitutionally ineffective; and (9) the cumulative effect of these errors deprived petitioner of a fair trial. The district court granted petitioner a certificate of appealability as to all of these issues. See 28 U.S.C. § 2253(c); Fed. R.App. P. 22(b)(1). We affirm the district court’s denial of habeas relief, with the exception of its treatment of petitioner’s claim that police planted evidence against him, which we remand to the district court for discovery. I. FACTS The victim was abducted on September 27, 1984, at approximately 9:30 P.M., following a junior high school football game. Two adults and a fifteen-year-old student witnessed the abduction. All three indicated that the victim had been forced into a yellow car. At trial, both adults identified petitioner’s yellow car as looking like the car in which the victim was abducted. The day after the abduction, the student witness, Paulo Gomes, identified two men from a photo array, one of whom was petitioner, as similar to the man he had seen abduct the victim. At trial, the student again identified petitioner as looking like the man who forced the victim into the yellow car. The victim’s partially clad body was found at 11:00 A.M. the morning after the abduction in a field ten miles from the school. She had been.strangled and suffocated and had died several hours before her body was found. The pep club uniform she had been wearing at the time of the abduction was never found. There was duct tape in her hair and markings on her body indicating that she had been bound with tape around her wrists, arms, ankles, thighs, back, neck and face. There were also tape marks indicating placement over her nose and mouth. She had suffered bruising or abrasions to her face, neck, back and buttocks. Petitioner lived near the junior high school. On the night of the abduction, he had visited his brother’s family, who lived just three quarters of a mile from the school. He left his brother’s home between 9:15 P.M. and 9:30 P.M. The next morning, petitioner left his yellow car parked in front of his home and walked an eighth of a mile to a grocery store. There, petitioner stole a car and drove to the construction site where he worked. Petitioner told his boss that he had suffered a “mild coronary” the previous night and had been treated at a hospital. He further related that, as a result, he would have to quit his job. The boss described petitioner that morning as wide-eyed and very nervous. Petitioner collected his wages and left. Police arrested him later that morning for driving a stolen vehicle. On September 29, and again on October 4, 1984, police executed search warrants for petitioner’s home, where he lived alone, and his car. During the first search, officers found, among other things, a partially packed suitcase in petitioner’s home and a used feminine napkin under petitioner’s bed. At the time she was abducted, the victim had been menstruating. The used feminine napkin found in petitioner’s home, however, appeared to be of a different type than that found at the victim’s home. A week after the murder, a paper bag was found on the roof of the grocery store located near petitioner’s home and near where he stole the car on the morning following the abduction. Inside the bag was a used feminine napkin of the same type found at the victim’s home, containing blood of the same type as the victim. The bag also contained a knife, a belt matching markings made on the victim’s arms, a fingernail that did not match either petitioner or the victim, several pieces of duct tape, including a wad of tape with hair stuck to it, a garment label, several cigarette butts, and an earring similar to that worn by the victim on the night she was abducted. At trial, the State presented the testimony of a forensic chemist, Janice Davis. Her testimony linked the victim, the contents of the paper bag, petitioner, his car, the stolen car, and petitioner’s home. Among other things, the chemist identified hair similar to the victim’s found on and underneath a bed, on a couch, and in the living room in petitioner’s home; in a glove found in the stolen car; in petitioner’s yellow car; and on the duct tape in the paper bag. In addition, fibers found on the victim’s body were similar to carpet fibers taken from petitioner’s car, floor mats and his home, including those from an afghan in his living room. Fibers found in petitioner’s living room, bedroom, and hair brush, and from the knife found in the paper bag on the grocery store roof, were similar to fibers taken from pep club uniforms like the one worn by the victim on the night of the abduction. A single limb hair found on the victim was similar to petitioner’s limb hair. The chemist testified that, based upon the hair, fiber and serological evidence, she was convinced that the victim had been in petitioner’s car and home. The jury convicted petitioner of first degree murder and kidnaping. During the capital sentencing proceeding, the trial court incorporated all of the guilt phase evidence. In addition, the State presented evidence of petitioner’s prior felony convictions for attempted first degree rape, aggravated kidnaping, indecency with a child, assault and battery with a dangerous weapon, child beating, and robbery with a dangerous weapon. A woman who had previously lived with petitioner also testified concerning an incident when petitioner entered her home, tied her up and stared at her. The woman’s daughter testified that petitioner sexually abused her. She also testified concerning an incident during which petitioner awakened the witness, then five or six years old, and her two brothers, then ages four and eight, in the middle of the night, tied them up without clothes and then stared at them while they struggled to get free. One of petitioner’s former wives testified to petitioner’s abusive behavior towards her and their children, including incidents when he would tie her up, rape her and then attempt to choke or smother her. In mitigation, petitioner presented evidence of his regular involvement with his church, his generally polite and kind demeanor, his father’s abuse, other incidents of petitioner’s abuse of women and children, his significant mental health problems exacerbated by his drinking, and his good behavior while in prison. A defense psychologist specifically testified that petitioner suffers from an incurable borderline personality disorder, primarily due to his father’s abuse, but that he could function well in a structured prison environment. The psychologist indicated that petitioner would probably remain a threat if released back into society, but that he did not present a threat to anyone in prison. The jury found the existence of three aggravating circumstances: petitioner had previously been convicted of a violent felony, he presented a continuing threat to society, and the murder was especially heinous, atrocious or cruel. The jury sentenced petitioner to death on the first degree murder conviction and to 999 years’ imprisonment on the kidnaping conviction. The Oklahoma Court of Criminal Appeals affirmed petitioner’s convictions and sentences. See Moore v. State, 788 P.2d 387 (Okla.Crim.App.1990). The United States Supreme Court denied certiorari. See Moore v. Oklahoma, 498 U.S. 881, 111 S.Ct. 227, 112 L.Ed.2d 182 (1990). Petitioner then sought state post-conviction relief, which the Oklahoma Court of Criminal Appeals denied. See Moore v. State, 889 P.2d 1253 (Okla.Crim.App.1995). The United States Supreme Court again denied certiorari. See Moore v. Oklahoma, 516 U.S. 881, 116 S.Ct. 215, 133 L.Ed.2d 146 (1995). Petitioner commenced this proceeding seeking federal habeas relief from his murder conviction and death sentence. See 28 U.S.C. § 2254. II. APPLICABILITY OF THE ANTI-TERRORISM AND EFFECTIVE DEATH PENALTY ACT OF 1996 A. Commencement of Habeas Proceeding On cross appeal, respondent argues that the district court erred in finding that the date petitioner filed a request for the appointment of counsel determined the date the habeas corpus action was filed and therefore concluding the Antiterrorism and Effective Death Penalty Act of 1996 (effective April 24, 1996) (AEDPA) did not govern. We agree and hold that the date of filing the petition, not the date of appointment of counsel, was the correct date for determining whether AEDPA governs. Petitioner filed his request for appointment of counsel on December 22, 1995, pursuant to 21 U.S.C. § 848(q)(4)(B), which provides for the appointment of counsel to indigent prisoners challenging a capital conviction or sentence “[i]n any post-conviction proceeding under [§ ] 2254.” The district court granted the request on December 27. Petitioner filed his habeas petition on July 1, 1996. The district court determined that although the habeas petition was filed after the effective date of AEDPA, the request for appointment of counsel, filed pre-AEDPA, actually commenced the proceedings thereby precluding AEDPA’s application. The district court relied on McFarland v. Scott, 512 U.S. 849, 114 S.Ct. 2568, 129 L.Ed.2d 666 (1994). In McFarland, the Supreme Court held that if a capital defendant invokes his right to appointed counsel under § 848(q)(4), he has a post-conviction proceeding pending and thus need not file a habeas corpus petition before a federal court may enter a stay of execution. See McFarland, 512 U.S. at 858-59, 114 S.Ct. 2568 (citing 28 U.S.C. § 2251, which permits a federal court to issue a stay “for any matter involved in the habeas corpus proceeding”). McFarland, however, recognized that neither the federal habeas corpus statute nor the rules governing habeas proceedings define a proceeding under § 2254 or state how such a proceeding shall be commenced. See id. at 854, 114 S.Ct. 2568. The Court also recognized that § 848(q)(4) ‘indicates that the right to appointed counsel adheres prior to the filing of a formal, legally sufficient habeas corpus petition,” because “a ‘post conviction proceeding’ within the meaning of § 848(q)(4)(B) is commenced by the filing of a death row defendant’s motion requesting the appointment of counsel for his federal habeas corpus proceeding.” McFarland, 512 U.S. at 854-55, 856-57, 114 S.Ct. 2568; see also id. at 857 n. 3, 114 S.Ct. 2568 (“preapplication legal assistance” included in § 848(q)(4)(B)). Indeed, the assistance of an attorney may be crucial before the actual filing of the petition. See id. at 854-56, 114 S.Ct. 2568. The Court then determined that to give meaning to the right to appointed counsel, the district court must be allowed to stay an execution under § 2251, regardless of whether the petitioner had filed a habeas petition. See McFarland, 512 U.S. at 858, 114 S.Ct. 2568. Notably, McFarland does not hold that appointment of counsel also commences a post-conviction proceeding within the meaning of § 2254. Cf. Williams v. Cain, 125 F.Bd 269, 274 (5th Cir.1997) (stating McFarland does not determine what date habeas petition is “pending” for applicability of substantive statutes), cert. denied, — U.S. -, 119 S.Ct. 144, 142 L.Ed.2d 116 (1998). McFarland merely ensured indigent capital defendants the right to counsel established by § 848(q)(4). See Williams, 125 F.3d at 274. Respondent argues that Lindh v. Murphy, 521 U.S. 320, 117 S.Ct. 2059, 138 L.Ed.2d 481 (1997), not McFarland, defined AEDPA’s applicability. Respondent notes that Lindh, 521 U.S. at 326, 327, 117 S.Ct. 2059, stated that AEDPA applied to cases filed after its enactment and that AEDPA referred to “ ‘an application for a writ of habeas corpus.’ ” Br. of Appellee, Cross-Appellant at 7 (quoting 28 U.S.C. §§ 2244(d)(1), 2254(a)). Thus, respondent maintains the date of the request for appointment of counsel does not determine whether AEDPA applies. Lindh held that AEDPA did not apply to habeas corpus applications pending when it was passed. See Lindh, 521 U.S. at 322-23, 327, 336, 117 S.Ct. 2059. Lindh did not expressly define when a habeas case is pending for purposes of the applicability of AEDPA. Although neither McFarland nor Lindh addressed what constitutes a pending ha-beas corpus proceeding for purposes of determining the applicability of AEDPA, the majority of circuits considering the issue have held that a case is pending for purposes of AEDPA only when the habeas petition is filed. See, e.g., Gosier v. Welborn, 175 F.3d 504, 506 (7th Cir.1999), petition for cert. filed (U.S. July 14, 1999) (No. 99-5282); Williams v. Coyle, 167 F.3d 1036, 1037, 1040 (6th Cir.1999); Nobles v. Johnson, 127 F.3d 409, 414 (5th Cir.1997), cert. denied, 523 U.S. 1139, 118 S.Ct. 1845, 140 L.Ed.2d 1094 (1998). Those circuits recognized that Lindh and McFarland did not address and did not resolve the issue before them and that McFarland focused on the need to expand the ordinary meaning of a pending case to give effect to Congressional intent. See Williams, 167 F.3d at 1038-39; Holman v. Gilmore, 126 F.3d 876, 879-80 (7th Cir.1997); Nobles, 127 F.3d at 413-14. As support for its conclusion that a federal habeas corpus case is filed upon the filing of the habeas petition, the Sixth Circuit looked at the language of 28 U.S.C. § 2254(e) which refers “to a proceeding instituted by an application for a writ of habeas corpus”; 28 U.S.C. § 1914(a) which requires payment of a filing fee upon the filing of an “application for a writ of habe-as corpus”; and Rule 1 of the Rules Governing § 2254 Cases which provides that the rules “govern the procedure in the United States district courts on applications under 28 U.S.C. § 2254.” See Williams, 167 F.3d at 1038. The Seventh Circuit did not disagree that an application for counsel under § 848(q)(4) is a case that may be reviewed by an appellate court. See Gosier, 175 F.3d at 506. “But a request for counsel under § 848(q)(4), part of Title 21, is not a case under Chapter 15S of Title 28 — that is, the request is not a collateral attack on a criminal judgment.” Gosier, 175 F.3d at 506. “[T]he motion for counsel is not itself a petition, because it does not call for (or even permit) a decision on the merits. And it is ‘the merits’ that the amended § 2254(d)(1) is all about.” Holman, 126 F.3d at 880. Unlike the other circuits, the Ninth Circuit defines a pending federal habeas petition more broadly. See Nino v. Galaza, 183 F.3d 1003, 1005 (9th Cir.1999). It has held that a habeas case begins with the appointment of counsel. See Calderon v. United States Dist. Court for the Cent. Dist. of Cal., 163 F.3d 530, 539-40 (9th Cir.1998) (en banc), cert. denied, — U.S. -, 119 S.Ct. 1377, 143 L.Ed.2d 535 (1999). Calderon based its decision on Hohn v. United States, 524 U.S. 236, 118 S.Ct. 1969, 141 L.Ed.2d 242 (1998). Hohn held that an application for a certificate of appealability constituted a case under 28 U.S.C. § 1254, and therefore the Supreme Court had jurisdiction to review a court of appeals’ denial of an application for a certificate of appealability. See Hohn, 524 U.S. at 238-89, 241, 253, 118 S.Ct. 1969. In reaching this decision, Hohn looked to Ex parte Quirin, 317 U.S. 1, 24, 63 S.Ct. 2, 87 L.Ed. 3 (1942), which held that a district court’s denial of a request for leave to file a petition for a writ of habeas corpus was a reviewable case on appeal. See Hohn, 524 U.S. at 246, 118 S.Ct. 1969. Hohn is distinguishable. We agree with the Sixth Circuit that Hohn and Ex parte Quirin stand only for the proposition that the denial by the district court of a motion for the issuance of a [certificate of appealability], a motion for leave to file a petition for the writ, or, as in our case, a motion for the appointment of counsel ... would constitute an appealable case. This does not imply, however, that the petitioner’s ha-beas corpus case has been initiated by the filing of such a preliminary motion. Although the Court in Hohn rejected the contention that the filing of a preliminary motion “should be regarded as a threshold inquiry separate from the merits,” Hohn, [524 U.S. at -, 118 S.Ct. at 1974], the holding and logic of the case were limited to the determination that the rejection by the district court of the preliminary motion constitutes an appealable case. Williams, 167 F.3d at 1040; see also Calderon, 163 F.3d at 545 (Hall, J., dissenting) (distinguishing Hohn’s use of word “case” to interpret whether Supreme Court had jurisdiction from use of word “case” to interpret whether statute of limitations had run under AEDPA). Accordingly, this court joins the majority of circuits in holding that a case is pending under AEDPA only upon the filing of a petition for writ of habeas corpus. The filing of a request for counsel to prepare a habeas petition does not govern the applicability of AEDPA as it is not a petition seeking substantive relief. B. Retroactivity Petitioner argues that if this court holds that the case commenced at the time he filed the habeas corpus petition, it is unconstitutional to retroactively apply the new standards of review set forth in AED-PA to state court proceedings completed before enactment or effectiveness of AED-PA. This court has held to the contrary, determining that AEDPA applies to cases filed after its effective date, regardless of when state court proceedings occurred. See Rogers v. Gibson, 173 F.3d 1278, 1282 n. 1 (10th Cir.1999); see also Berget v. Gibson, No. 98-6381, 1999 WL 586986 (10th Cir. Aug.5, 1999) (unpublished order and judgment citing Rogers and holding that application of AEDPA to cases filed after its effective date is not impermissibly retroactive); Mueller v. Angelone, 181 F.3d 557, 565-73 (4th Cir.) (addressing argument similar to that raised here and holding AEDPA does not have impermissible retroactive effect), cert. denied, — U.S. -, 120 S.Ct. 37, — L.Ed.2d - (1999). C. Standards of Review The review of a denial of habeas corpus relief is subject to two different types of analysis depending on whether a claim was heard on its merits by the state courts. “If the claim was not heard on the merits by the state courts, and the federal district court made its own determination in the first instance, we review the district court’s conclusions of law de novo and its findings of fact, if any, for clear error.” LaFevers v. Gibson, 182 F.3d 705, 711 (10th Cir.1999). If a claim was adjudicated on its merits by the state courts, a petitioner will be entitled to federal habeas relief only if he can establish that the state court decision “was contrary to, or involved an unreasonable application of, clearly established Federal law, as determined by the Supreme Court of the United States,” 28 U.S.C. § 2254(d)(1), or “was based on an unreasonable determination of the facts in light of the evidence presented in the State court proceeding,” id. § 2254(d)(2). AEDPA thereby increases the degree of deference afforded to state court adjudications. See Boyd v. Ward, 179 F.3d 904, 912 (10th Cir.1999) (citing Houchin v. Zavaras, 107 F.3d 1465, 1470 (10th Cir.1997)). Petitioner argues that if AEDPA applies, this court must define the standards of review set forth in § 2254(d)(1). We have applied these standards, but have not defined them, beyond the precise wording of AEDPA. See Bryson v. Ward, 187 F.3d 1193, 1199 n. 3 (10th Cir.1999) (citing Matteo v. Superintendent, 171 F.3d 877, 885-91 (3d Cir.1999), petition for cert. filed, 67 U.S.L.W. 3008 (U.S. June 22, 1999) (No. 98-2050), and Nevers v. Killinger, 169 F.3d 352, 357-62 (6th Cir.), cert. denied, — U.S. -, 119 S.Ct. 2340, 144 L.Ed.2d 237 (1999), which set forth the various interpretations of the standards of deference afforded state court adjudications under both § 2254(d)(l)’s “contrary to” and “unreasonable application of’ language by other federal courts of appeals). The United States Supreme Court has granted certiorari to review the Fourth Circuit’s interpretation of these standards. See Williams v. Taylor, — U.S. -, 119 S.Ct. 1355, 143 L.Ed.2d 516 (1999); see also — U.S. -, 119 S.Ct. 1355, 143 L.Ed.2d 516 (1999) (listing issues presented). Under any possible interpretation of the standards, the outcome of this appeal would be the same. Thus, we decline to interpret the standards in this case. III. ALLEGATIONS OF PLANTED EVIDENCE Petitioner first argues that the district court erred in denying discovery on his claim that police officers planted evidence in his home and car, and did not disclose this fact, in violation of Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963). Petitioner asserts that police officers obtained hair from the victim’s body and fibers from a pep club uniform similar to the one worn by the victim on the night of the abduction, planted those in his home and car between the first and second searches, and then “discovered” this evidence during the execution of the second search warrant. To establish a Brady violation, petitioner bears the burden of showing that the prosecution suppressed material evidence favorable to petitioner. See, e.g., Moore v. Reynolds, 153 F.3d 1086, 1112 (10th Cir.1998), cert. denied, — U.S. -, 119 S.Ct. 1266, 143 L.Ed.2d 362 (1999). Knowledge of police officers or investigators will be imputed to the prosecution. See Kyles v. Whitley, 514 U.S. 419, 421, 437, 115 S.Ct. 1555, 131 L.Ed.2d 490 (1995); Smith v. Secretary of N.M. Dep’t of Corrections, 50 F.3d 801, 824-25 (10th Cir.1995). In support of this Brady claim, petitioner relies upon the statement of Bruce Hawkins, the mortician who prepared the victim’s body for burial. The Oklahoma Court of Criminal Appeals first considered this evidence in the state post-conviction proceeding, determining Hawkins’ statement “could not have been discovered with due diligence before trial, and is not cumulative of any evidence presented at trial.” Moore, 889 P.2d at 1257-58. The court further determined that this new evidence “certainly suggests that Midwest City police followed a somewhat unusual investigative procedure in this case.” Id. at 1257. Nonetheless, the Oklahoma appellate court declined to hold an evidentiary hearing or conduct any further factual inquiry. That court, instead, assumed the truth of petitioner’s factual allegations and denied relief, holding that “mere evidence of unusual conduct on the detectives’ part, when evaluated in the context of the entire record, is not material, and does not create a reasonable probability that the trial’s outcome would be changed.” Id. at 1257-58. The determination of whether undisclosed evidence is material is a mixed question of law and fact reviewed de novo by this court prior to AEDPA. See United States v. Trujillo, 136 F.3d 1388, 1393 (10th Cir.) (direct criminal appeal), cert. denied, — U.S. -, 119 S.Ct. 87, 142 L.Ed.2d 69 (1998); see also Newsted v. Gibson, 158 F.3d 1085, 1094 (10th Cir. 1998) (reviewing de novo Brady claim asserted in pre-AEDPA habeas petition), cert. denied, — U.S. -, 119 S.Ct. 1509, 143 L.Ed.2d 661 (1999). In this appeal governed by AEDPA, therefore, we consider whether the state appellate court’s materiality determination amounts to an “unreasonable application” of clearly established Supreme Court precedent. 28 U.S.C. § 2254(d)(1). We conclude it does. Suppressed exculpatory evidence will be deemed material “only if there is a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different. A ‘reasonable probability’ is a probability sufficient to undermine confidence in the outcome.” Pennsylvania v. Ritchie, 480 U.S. 39, 57, 107 S.Ct. 989, 94 L.Ed.2d 40 (1987) (further quotation omitted); see also Strickler v. Greene, — U.S. -, -, 119 S.Ct. 1936, 1948, — L.Ed.2d -, -(1999). “The question is not whether the defendant would more likely than not have received a different verdict with the evidence, but whether in its absence he received a fair trial, understood as a trial resulting in a verdict worthy of confidence.” Kyles, 514 U.S. at 434, 115 S.Ct. 1555. The State’s case against petitioner was entirely circumstantial. The existence and cross-transference of the fiber and hair evidence was crucial to the State’s case against him. If proved, petitioner’s allegations that police officers planted this evidence, therefore, would be material—i.e., there is a reasonable probability that the result of the proceeding would have been different. Petitioner’s allegations, therefore, if proved would entitle him to habeas relief. It remains for petitioner to prove the truth of those allegations. We, therefore, turn to the question of whether petitioner is entitled to discovery on this claim. See Bracy v. Gramley, 520 U.S. 899, 905-06, 117 S.Ct. 1793, 138 L.Ed.2d 97 (1997). A federal habeas petitioner will be entitled to discovery only “if, and to the extent that, the [district court] judge in the exercise of his discretion and for good cause shown grants leave to do so, but not otherwise.” Rule 6(a), Rules Governing Section 2254 Cases; see also LaFevers, 182 F.3d at 723. “ ‘[W]here specific allegations before the court show reason to believe that the petitioner may, if the facts are fully developed, be able to demonstrate that he is ... entitled to relief, it is the duty of the court to provide the necessary facilities and procedures for an adequate inquiry.’ ” Bracy, 520 U.S. at 908-09, 117 S.Ct. 1793 (quoting Harris v. Nelson, 394 U.S. 286, 300, 89 S.Ct. 1082, 22 L.Ed.2d 281 (1969)). Petitioner has met this burden here. In his statement, Hawkins asserts that two detectives returned to the funeral home on three separate occasions to obtain samples of the victim’s pubic, scalp and limb hairs. They apparently returned the second time because, during the first visit, they had cut the hairs, instead of plucking them. On the third occasion, the detectives took up to two and one-half hours to obtain additional evidence. The trial record corroborates part of Hawkins’ statement, indicating that detectives did go to the funeral home several times to obtain additional samples of the victim’s hair, after completion of the medical examiner’s examination. Detective Marston testified that he and Detective Howard went to the funeral home on Monday, October 1, 1984, to obtain the victim’s fingerprints. Pursuant to the forensic chemist’s request, Detective Ingle also went to the funeral home on October 1 to obtain samples of the victim’s limb hair. In his statement, Hawkins further asserts that another funeral home employee, John Boeing, who is now deceased, followed the detectives after their second visit to the funeral home. According to Hawkins, Boeing told him that the detectives went directly from the funeral home to petitioner’s home, where one entered through an open window, then unlocked the door from the inside. Hawkins asserts that they had with them a red sweater and the victim’s hair samples they had just collected at the funeral home. The detectives remained in petitioner’s home for some time, and then subsequently “appeared to be doing things” to petitioner’s yellow car, which was parked in front of his home. Later that evening, Hawkins accompanied Boeing to petitioner’s home and confirmed that a window remained open. According to Hawkins, both he and Boeing followed the detectives to petitioner’s home after the detectives’ third visit to the funeral home. Hawkins asserts that the window to the home was still open at that time. The record confirms that key hair evidence was not discovered until the second search, on October 4, 1984. In addition, investigators did not discover the red fibers, consistent with pep club uniforms similar to the victim’s, until the second search. Even though no one had seen them during the first search, the forensic chemist discovered these red fibers near the front door of petitioner’s home, immediately upon her entry of the home to conduct the second search. During the second search, investigators also discovered similar red fibers located under petitioner’s bed, in the same location where, during the first search, a used feminine napkin had been discovered. At trial, detectives gave contradictory testimony concerning whether they had obtained two or three pep club sweaters to compare with any fibers found. Detectives Howard and Garner both testified that they had obtained three such sweaters, two new and one used, as part of three complete pep club outfits to be used for any necessary comparisons. Detective Garner later testified, however, that he submitted only two sweaters to the forensic chemist for analysis. The forensic chemist testified that she had only requested two sweaters for analysis, one new and one used. No one could account for the whereabouts of the third sweater. There was also contradictory testimony at trial concerning whether, and in what manner, police officers had secured petitioner’s home after the first search. The trial record, therefore, lends some support and does not contravene petitioner’s allegations which, if proved, would warrant habeas relief. In light of those specific allegations, supported by Hawkins’ statement, the district court abused its discretion in denying discovery. See Bracy, 520 U.S. at 909, 117 S.Ct. 1793. We, therefore, remand for limited discovery on this one ground for habeas relief. In remanding, however, we note that “Rule 6(a) makes it clear that the scope and extent of such discovery [remains] a matter confided to the discretion of the District Court.” Bracy, 520 U.S. at 909, 117 S.Ct. 1793. IV. EXPERT TESTIMONY OF FORENSIC CHEMIST Petitioner next argues that the trial court’s admission of the expert testimony of the State’s forensic chemist, Janice Davis, concerning hair and fiber evidence linking petitioner to the crime, deprived petitioner of due process and a fair trial. On direct appeal, petitioner challenged Davis’ testimony only on state law grounds. See Duncan v. Henry, 513 U.S. 364, 366, 115 S.Ct. 887, 130 L.Ed.2d 865 (1995) (per curiam) (“If a habeas petitioner wishes to claim that an evidentia-ry ruling at a state court trial denied him the due process of law guaranteed by the Fourteenth Amendment, he must say so, not only in federal court, but in state court.”). Because respondent does not argue that this claim is unexhausted or procedurally barred, however, we address the merits of petitioner’s federal claim. See 28 U.S.C. § 2254(b)(2) (federal habeas court may deny relief on merits of unexhausted claim); see also Hooks v. Ward, 184 F.3d 1206, 1216-1217 (10th Cir.1999) (State is obligated to raise procedural default as affirmative defense or lose right to do so). Because the state courts did not address the federal claim, however, the district court addressed the merits of this issue in the first instance. This court, therefore, reviews the legal conclusions underlying the district court’s decision de novo, and any factual findings for clear error. See LaFevers, 182 F.3d at 711. Petitioner is not entitled to federal habeas relief unless “the error, if any, was so grossly prejudicial that it fatally infected the trial and denied the fundamental fairness that is the essence of due process.” Williamson v. Ward, 110 F.3d 1508, 1522 (10th Cir.1997) (pre-AEDPA). The district court determined that any question concerning the admission of Davis’ testimony did not rise to the level of a due process violation. Petitioner argues this evidence was unduly prejudicial because it was unreliable, inaccurate or false; the nature of hair and fiber comparisons is inexact; Davis testified in a biased and subjective manner; and she was “probably” unqualified to testify as an expert. Hair and fiber comparison evidence is not per se inadmissible. See id. at 1522-23 (addressing admissibility of hair analysis evidence). Davis did possess expertise in hair and fiber analysis, having been trained in forensic science generally and having attended several law enforcement training seminars specifically addressing hair and fiber analysis. See Story v. Collins, 920 F.2d 1247, 1255 (5th Cir.1991) (addressing admission of expert testimony concerning sexually-abused children). We cannot say that it was fundamentally unfair for the trial court to allow her to testify as an expert. See Bennett v. Lockhart, 39 F.3d 848, 857 (8th Cir.1994). On cross-examination and in argument before the trial judge, defense counsel ably challenged the hair and fiber evidence, Davis’ qualifications, and her testing methods. See Little v. Johnson, 162 F.3d 855, 863 & n. 11 (5th Cir.1998) (citing Barefoot v. Estelle, 463 U.S. 880, 898-99, 103 S.Ct. 3383, 77 L.Ed.2d 1090 (1983)), cert. denied, — U.S. -, 119 S.Ct. 1768, 143 L.Ed.2d 798 (1999); see also Adams v. Leapley, 31 F.3d 713, 715 (8th Cir.1994). He also had a defense expert available to guide and inform his cross-examination. Cf. Little, 162 F.3d at 863 (counsel could offer rebuttal expert evidence and cross-examine purported state expert). Davis, herself, testified that a comparison of hairs could only establish either that the known and unknown hairs were not from the same source, or that the hairs were microscopically similar and, therefore, could have come from the same source. She also stressed that hair comparison could not result in a positive identification. The trial court instructed the jury that it was to determine the weight to be given any expert testimony. See Little, 162 F.3d at 863; Bachman v. Leapley, 953 F.2d 440, 442 (8th Cir.1992). “Because this eviden-tiary issue was fully and competently aired in the state courts,” petitioner has failed to show a “violation of fundamental fairness under the due process clause.” Spence v. Johnson, 80 F.3d 989, 1000 (5th Cir.1996). In support of this federal habeas claim, petitioner submits the affidavit of another hair and fiber expert who further challenges the credibility of Davis’ testimony and testing methods. Based upon the affidavit, petitioner asserts he is entitled to discovery on this claim. This evidence, however, was available to petitioner at trial. In addition, he had a defense expert at trial to inform his challenge to this evidence. Cf. Siripongs v. Calderon, 167 F.3d 1225, 1227-28 (9th Cir.1999) (rejecting habeas claims based upon opinion of newly-hired defense expert, where test results were available and reviewed by defense expert prior to trial). Petitioner, therefore, has failed to establish good cause for discovery on this issue. See Rule 6(a), Rules Governing Section 2254 Cases; see also Bracy, 520 U.S. at 908-09, 117 S.Ct. 1793. V. REMOVAL OF VENIRE MEMBER Petitioner argues the trial court violated his Sixth, Eighth, and Fourteenth Amendment rights by improperly removing a venire member for cause without allowing him an opportunity to rehabilitate the juror. “ ‘[A] juror may not be challenged for cause based on his views about capital punishment unless those views would prevent or substantially impair the performance of his duties as a juror in accordance with his instructions and his oath.’ ” Wainwright v. Witt, 469 U.S. 412, 420, 105 S.Ct. 844, 83 L.Ed.2d 841 (1985) (quoting Adams v. Texas, 448 U.S. 38, 45, 100 S.Ct. 2521, 65 L.Ed.2d 581 (1980)) (emphasis omitted). A trial judge’s determination of a potential juror’s bias under this standard is a factual finding entitled to a presumption of correctness. See id. at 428-29, 105 S.Ct. 844 (pre-AEDPA); Davis v. Executive Dir. of Dep’t of Corrections, 100 F.3d 750, 777 (10th Cir.1996) (same); see also Pitsonbarger v. Gramley, 141 F.3d 728, 734 (7th Cir.) (applying AEDPA), cert. denied, — U.S. -, 119 S.Ct. 448, 142 L.Ed.2d 402 (1998); Fuller v. Johnson, 114 F.3d 491, 500-01 (5th Cir.1997) (same). In making such a determination, the trial judge must assess the credibility of the prospective juror, a task an appellate court cannot easily do based upon a record. See Witt, 469 U.S. at 429, 105 S.Ct. 844; see also Castro v. Ward, 138 F.3d 810, 824 (10th Cir.) (“Because issues of credibility and demeanor are crucial to the trial judge’s determination, our review of that determination is quite deferential.”), cert. denied, — U.S. -, 119 S.Ct. 422, 142 L.Ed.2d 343 (1998). Petitioner argues that a juror who opposes the death penalty may not be excused for cause if he is able to follow the trial judge’s instructions and set aside his own beliefs in deference to the law. Here, petitioner maintains the trial judge did not properly question the prospective juror to determine whether he could do so. The following colloquy occurred: THE COURT: Mr. Parrish, I will ask you, the defendant in this case is charged with murder in the first degree. It is your duty to determine whether the defendant is not guilty or guilty of murder in the first degree. The law provides that the punishment for murder in the first degree is life or death. If you find beyond a reasonable doubt that the defendant is guilty of murder in the first degree, can you consider both legal punishments, life or death? MR. PARRISH: No. THE COURT: Let me ask you this question, sir. If you found beyond a reasonable doubt that the defendant was guilty of murder in the first degree and if, under the evidence, facts and circumstances of the case, the law would permit you to consider a sentence of death, are your reservations about the death penalty such that regardless of the law, the facts and circumstances of the case, you would not consider inflicting the death penalty? MR. PARRISH: Yes. Tr. vol. I at 60-61. After the prosecution moved to excuse the juror, defense counsel asked for a bench conference, during which he requested an opportunity to further question the juror. MR. RAVITZ: Judge, we contend that two questions can not properly determine a juror’s feelings, and if we’re not allowed to explore, this Court can not make any type of factual judgment on it. We would request that we be permitted to ask the juror — explain to the juror the law, the fact that all he is required to do is consider the death penalty, that this defendant is entitled to a representative jury of his peers, that if the juror wants to consider it and reject it, he has that right to do it as long as he’s willing to consider it. That as long as he is willing — as long as it will not affect his decision on guilt or innocence, he has a right to sit on it. If you don’t let me inquire on this, we can’t make — this record will be totally insufficient for an appellate court to review whether this Court was correct in excusing him. When I finish, the Court may be entirely correct in excusing, but I think I’m entitled to that opportunity. Id. at 62-63. The trial court overruled defense counsel’s request and excused the juror. On direct criminal appeal, the Oklahoma Court of Criminal Appeals held that the juror was properly excluded under Witt because the trial court’s questioning established he would not consider imposing the death penalty in a proper case. See Moore, 788 P.2d at 397. That court determined the trial court did not err in disallowing further questioning by defense counsel, because further questioning may have resulted in confusion and the relevant questions had been asked and clearly answered. See id. Petitioner contends that the second question asked by the trial court “is virtually identical to a question this Court described as ‘confusing, and because of its negative phrasing, invites ambiguous answers.’” Appellant’s Opening Br. at 44 (quoting Davis v. Maynard, 869 F.2d 1401, 1408 (10th Cir.1989), vacated on other grounds by Saffle v. Davis, 494 U.S. 1050, 110 S.Ct. 1516, 108 L.Ed.2d 756 (1990), opinion reinstated in part by Davis v. Maynard, 911 F.2d 415, 418 (10th Cir.1990)). The following question was at issue in Davis: If you found beyond a reasonable doubt that the Defendant in this case was guilty of Murder in the First Degree and if under the evidence, facts and circumstances of the ease the law would permit you to consider a sentence of death, are your reservations about the Death Penalty such that regardless of the law, the facts and the circumstances of the case, you would not inflict the Death Penalty? Davis, 869 F.2d at 1408. This court determined that a “no” answer to this question could ambiguously mean either that the juror could not inflict the death penalty despite the law and evidence or that any reservations the juror had would not impair the juror’s ability to inflict the proper sentence. See id. at 1408-09. Davis, however, refused to conclude that the exclusion of the juror for cause was reversible error. See id. at 1409. In so refusing, Davis looked to Witt where the Supreme “Court established that prospective jurors’ bias towards the death penalty need not be proved with ‘unmistakable clarity’ ” in order to excuse a juror for cause. Id. (quoting Witt, 469 U.S. at 424, 105 S.Ct. 844). This is because determinations of juror bias cannot be reduced to question-and-answer sessions which obtain results in the manner of a catechism. What common sense should have realized experience has proved: many veniremen simply cannot be asked enough questions to reach the point where their bias has been made “unmistakably clear”; these-veniremen may not know how they will react when faced with imposing the death sentence, or may be unable to articulate, or may wish to hide their true feelings. Despite this lack of clarity in the printed record, however, there will be situations where the trial judge is left with the definite impression that a prospective juror would be unable to faithfully and impartially apply the law... .[T]his is why deference must be paid to the trial judge who sees and hears the juror. Witt, 469 U.S. at 424-26, 105 S.Ct. 844 (footnote omitted). Thus, even where there is ambiguity, the trial court, aided by its assessment of the juror’s credibility, may resolve the ambiguity in favor of the State. See id. at 434, 105 S.Ct. 844. Nor do we believe the trial court was required to afford petitioner an opportunity to further examine and rehabilitate the juror. “[P]art of the guarantee of a defendant’s right to an impartial jury is an adequate voir dire to identify unqualified jurors.” Morgan v. Illinois, 504 U.S. 719, 729, 112 S.Ct. 2222, 119 L.Ed.2d 492 (1992). Here, the voir dire was adequate to detect whether the prospective juror would have been qualified to serve as a juror. See Yeatts v. Angelone, 166 F.3d 255, 265 (4th Cir.) (corollary of right to impartial jury is requirement of voir dire sufficient to identify unqualified jurors), cert. denied, — U.S. -, 119 S.Ct. 1517, 143 L.Ed.2d 668 (1999). Thus, the trial court was not constitutionally required to grant defense counsel an opportunity to conduct a searching inquiry. Cf. Sellers v. Ward, 135 F.3d 1333, 1341 (10th Cir.) (where defense attorney wanted to inquire whether prospective jurors would find specific facts mitigating), cert. denied, — U.S. -, 119 S.Ct. 557, 142 L.Ed.2d 463 (1998). The trial court’s decision not to permit further questioning by defense counsel did not exceed the bounds of that court’s considerable discretion. See Neely v. Newton, 149 F.3d 1074, 1083-84 (10th Cir.1998) (holding federal courts are deferential to what questions should be asked), cert. denied, — U.S. -, 119 S.Ct. 877, 142 L.Ed.2d 777 (1999). Even assuming additional questions would have been helpful, the trial court’s failure to allow defense counsel to ask the questions did not render the trial fundamentally unfair. See id. at 1084. Petitioner has failed to rebut the presumption the trial court was correct in finding that the juror’s views would have prevented or substantially impaired his performance of his duties as a juror. The Oklahoma Court of Criminal Appeals’ determination that the juror’s answers clearly indicated that he could not consider imposing the death penalty regardless of the evidence and the instructions was not contrary to or an unreasonable application of Witt. VI. PROSECUTORIAL MISCONDUCT Petitioner alleges the prosecution engaged in misconduct at both stages of his trial by: (1) eliciting sympathy for the victim; (2) vouching for the credibility of state witnesses; (3) stating personal opinion about petitioner’s guilt; and (4) undermining the jury’s sense of responsibility in selecting the appropriate punishment. On direct criminal appeal, petitioner raised only the first claim and did so only on state law grounds. The Oklahoma Court of Criminal Appeals determined that state law was not violated. See Moore, 788 P.2d at 401. On post-conviction, petitioner raised all four claims, doing so on state law grounds with respect to the first three and on federal grounds with respect to the fourth. Without citing state or federal law, the Oklahoma Court of Criminal Appeals recognized that the prosecutor’s comments occasionally skirted the boundaries of permissible argument, but considered in the context of the entire closing arguments, did not require reversal or modification. The court determined the prosecutor primarily made permissible comments based on the evidence or merely responded to defense counsel’s closing arguments. See Moore, 889 P.2d at 1255 n. 4. Because respondent does not argue petitioner failed to exhaust the first three claims on federal grounds and does not argue procedural bar with respect to all four claims, we address the merits of all claims. See 28 U.S.C. § 2254(b)(2) (permitting federal court to deny relief on merits of unexhausted claim); Hooks, 184 F.3d 1206, 1216-1217 (holding State must raise procedural bar or it is waived). The federal district court addressed the merits of the first three claims on federal law grounds in the first instance. We review the district court’s legal conclusions de novo and its factual findings for clear error. See LaFevers, 182 F.3d at 711. We assume the state appellate court reviewed the merits of the fourth claim under federal law, as petitioner requested. Accordingly, we review the Oklahoma Court of Criminal Appeals determinations on the fourth claim for reasonableness. See 28 U.S.C. § 2254(d)(1). Allegations of prosecutorial misconduct are mixed questions of law and fact. See Fero v. Kerby, 39 F.3d 1462, 1473 (10th Cir.1994). Not every improper and unfair remark made by a prosecutor will amount to a federal constitutional deprivation. See Caldwell v. Mississippi, 472 U.S. 320, 338, 105 S.Ct. 2633, 86 L.Ed.2d 231 (1985). A prosecutor’s improper comment or argument will require reversal of a state conviction only where the remarks sufficiently infect the trial so as to make it fundamentally unfair and, therefore, a denial of due process. See Donnelly v. DeChristoforo, 416 U.S. 637, 643, 645, 94 S.Ct. 1868, 40 L.Ed.2d 431 (1974); see also Darden v. Wainwright, 477 U.S. 168, 181, 106 S.Ct. 2464, 91 L.Ed.2d 144 (1986); Hoxsie v. Kerby, 108 F.3d 1239, 1243 (10th Cir.1997). Inquiry into the fundamental fairness of a trial can be made only after examining the entire proceedings. See Donnelly, 416 U.S. at 643, 94 S.Ct. 1868. To view the prosecutor’s statements in context, we look first at the strength of the evidence against the defendant and decide whether the prosecutor’s statements plausibly could have tipped the scales in favor of the prosecution.... We also ascertain whether curative instructions by the trial judge, if given, might have mitigated the effect on the jury of the improper statements.... When a prosecutor responds to an attack made by defense counsel, we evaluate that response in light of the defense argument.... Ultimately, we must consider the probable effect the prosecutor’s [statements] would have on the jury’s ability to judge the evidence fairly- Fero, 39 F.3d at 1474 (quotations omitted). With these standards in mind, we turn to petitioner’s individual claims of prosecuto-rial misconduct. A. Eliciting Sympathy for the Victim Petitioner first argues that during closing arguments at both stages, the prosecution sought to ensure a conviction and death sentence by appealing to the emotions of the jury and attempting to elicit sympathy for the victim. During the first stage closing arguments, the prosecutor referred to the victim by a nickname not supported by the evidence. Also, the prosecutor asked the jury to speculate about what may have happened to the victim, despite admitting that he did not know exactly what .happened to her, and commented on the suffering of the victim’s family. During the second stage, the prosecution continued with its pleas for victim sympathy by speculating about what happened to the victim and her responses, pointing out the loss to her family, stating petitioner gets the benefit of the doubt but the victim did not despite her innocence, and stating that a death verdict was proper out of love for the victim and her parents and the past and the future victims of petitioner. To the extent the prosecutor speculated about what petitioner did to the victim, the federal district court determined the comments were a tenable explanation based on evidence and logical inferences from the evidence. With respect to the comments about the suffering of the victim’s mother and family, the federal district court determined the comments were improper, but petitioner failed to show the comments were so egregious as to render the trial fundamentally unfair, especially in light of the overwhelming evidence of guilt and the jury instructions regarding sympathy. This court does not condone prosecutorial remarks encouraging the jury to allow sympathy to influence its decision. See Duvall, 139 F.3d at 795. After reviewing the record, however, we cannot conclude the comments affected the outcome at either stage of trial. The prosecution’s speculations about what happened to the victim were reasonable possible inferences based on the evidence. Cf. Hooks, 184 F.3d 1206, 1221-1222 (references not “so far off the actual evidence nor so central to the prosecutor’s case that they were likely to have affected the jury’s verdicts”). The State’s evidence makes it probable that the murder of the young victim produced sympathy before the prosecution made any closing remarks. See Duvall, 139 F.3d at 795. “Some emotion is inevitable in capital sentencing[,]” and the prosecutor’s appeals to emotion in this case were not sufficient to render the argument improper. Coleman v. Brown, 802 F.2d 1227, 1239 (10th Cir.1986). The trial court instructed the jury at both stages to consider the evidence and testimony received at trial and not to allow sympathy to enter into its deliberations. These instructions, which the jury presumably followed, helped to mitigate the effect on the jury of any possible improper pros-ecutorial statements. See Fero, 39 F.3d at 1474. In light of the evidence and the instructions, this court is not persuaded that the prosecution’s remarks denied petitioner a fair trial or his right to due process. B. Vouching for the Credibility of State Witnesses In responding to the petitioner’s claim that evidence had been planted, the prosecutor apologized, on behalf of the State, to the officers who worked on the case, “the men who go out and work the streets and try to make this society safe.” According to petitioner, the prosecution was attempting to make the jurors feel a debt of gratitude to these officers, who had been wronged by petitioner’s challenge to their testimony. In addition, petitioner challenges the prosecutor’s comment that petitioner’s attack on the searches was an attack on both himself and another prosecutor. The federal district court determined that there had been no improper vouching, as the first instance was grandstanding and the second was merely skirting the boundaries, but did not warrant relief. Generally, prosecutors should not personally vouch for the credibility of state witnesses or place their own integrity and credibility in issue. See Hopkinson v. Shillinger, 866 F.2d 1185, 1209 (10th Cir.), reh’g on other grounds, 888 F.2d 1286 (10th Cir.1989). Here, however, the statements were made in response to comments of defense counsel. See Darden, 477 U.S. at 182, 106 S.Ct. 2464; see also Hopkinson, 866 F.2d at 1210 (recognizing that improper statement made in response to defense counsel’s arguments does not make statement proper, but it may affect context in which jury views improper statement). Also, the statements were made in isolation. See Donnelly, 416 U.S. at 647, 94 S.Ct. 1868 (determining court should not lightly infer prosecutor intended isolated, ambiguous remark to have most damaging meaning or that jury will draw that meaning from other less damaging interpretations); see also United States v. Ludwig, 508 F.2d 140, 143 (10th Cir.1974) (reversing conviction in direct criminal appeal where prosecutor vouched for integrity of state police and vouching was not isolated incident). Nor did the prosecutor cross the line from advocate to witness with these isolated statements. Furthermore, the trial court instructed the jury to consider the evidence in the case in making its decision. We conclude the remarks, viewed in the context of the entire trial, did not prejudice petitioner by influencing the jury to stray from its responsibility to be fair and unbiased. See United States v. Young, 470 U.S. 1, 12, 18, 105 S.Ct. 1038, 84 L.Ed.2d 1 (1985). C. Expressing Personal Opinion About Petitioner’s Guilt The prosecutor told the jury the odds that petitioner committed the crime are a quarter of a million to one. Petitioner argues that this statement jeopardized his right to be tried based on the evidence presented and instead indicated the jury should trust the government’s judgment over its own view of the evidence. See id. at 18-19,105 S.Ct. 1038. The federal district court determined this comment did not implicate any due process violations. See Duvall, 139 F.3d at 794. Although the prosecutor should not have expressed his personal opinion regarding guilt, there is no suggestion that, in doing so, he relied on evidence beyond that presented at trial. See Young, 470 U.S. at 19, 105 S.Ct. 1038. Moreover, the prosecutor also remarked that the jury should find petitioner guilty based on the evidence and not because the prosecution said he was guilty. D. Undermining Jury’s Responsibility in Selecting Punishment The prosecutor stated in his second stage closing argument that when he files a bill of particulars and asks for the death penalty, it is a proper case for the death penalty. Also, he informed the jury it is'“only one piece, one little cog in the community.” Additionally, the prosecutor told the jury that before any case can be presented to you for your consideration in terms of what sentence is appropriate in that sentence, a number of things have to happen. The decision—the evidence has to be brought before you upon which you can base that decision. It would be improper for you to go in that jury room and bring back a decision without having the proper evidence before you, as Mr. Dea-son and I have done. Prior to that time, decision has to be made as to what penalty will be sought in that case. That decision is then made. Prior to that time, before that kind of decision can be made, an investigation has to be made by the police department— —in this case. And the evidence has to be brought forth. That evidence has to be gathered. ' It was done in this case. Before that. Before that evidence can be gathered, the one person who voluntarily enters into this whole scene is [petitioner].... Tr. vol. VII at 1626-27. Petitioner believes that these statements violated Caldwell and were designed to make the jury surrender its judgment to the judgment of the prosecution and law enforcement, rather than to make a decision based on the strength of the evidence. On post-conviction review, the Oklahoma Court of Criminal Appeals, apparently deciding petitioner’s Caldwell argument, determined that these comments merely responded to petitioner’s counsel’s second stage closing argument. See Moore, 889 P.2d at 1255 n. 4. The federal district court determined that defense counsel invited these comments by his own comments regarding petitioner’s continuing threat to society, petitioner’s disease, the social and personal consequences of the jury’s decision, and the types of cases appropriate for the death penalty. Further, the district court determined the remarks did not place the ultimate sentencing decision on anyone other than the jury. See Caldwell, 472 U.S. at 328-29, 105 S.Ct. 2633. The court believed that the comments merely underscored the jury’s part in the system of justice. See Dutton v. Brown, 812 F.2d 593, 597 (10th Cir.1987). The prosecutor’s statements viewed in the context of the entire trial did not affirmatively mislead the jury regarding its responsibility for determining punishment, and thus did not violate Caldwell. See Romano v. Oklahoma, 512 U.S. 1, 8-9, 114 S.Ct. 2004, 129 L.Ed.2d 1 (1994). Furthermore, the trial court’s instructions informed the jury that it had the duty to determine the penalty to be imposed. We conclude the prosecutor’s statements did not render the death penalty verdict unreliable. See Sellers, 135 F.3d at 1343 (prosecutor’s suggestion that he personally approved of death penalty and statements that “many hurdles had to be jumped before a capital murder trial could ever occur” were insufficient to suggest that anyone other than jury had burden to make ultimate sentencing decision); see also Moore, 153 F.3d at 1113 (prosecutor’s comments that jury was small part of machinery to put petitioner on death row and prosecutor made decision to seek death penalty, even if improper, were not significant enough to influence jury’s sentencing decision); Parks v. Brown, 840 F.2d 1496, 1503-04 (10th Cir.1987) (prosecutor’s comments did not minimize importance of jury’s role in fixing sentence), rev’d on other grounds by Saffle v. Parks, 494 U.S. 484, 110 S.Ct. 1257, 108 L.Ed.2d 415 (1990). Petitioner has failed to show the Oklahoma Court of Criminal Appeals’ decision was contrary to or an unreasonable application of Caldwell. See 28 U.S.C. § 2254(d)(1). E. Combined Impact of Comments Even if the prosecutor’s comments viewed in isolation do not warrant relief, petitioner maintains that their combined impact does. “ ‘Cumulative-error analysis applies where there are two or more actual errors. It does not apply, however, to the cumulative effect of non-errors.’ ” Castro, 138 F.3d at 832 (quoting Hoxsie, 108 F.3d at 1245); see Newsted, 158 F.3d at 1097 (“A non-error and a nonprejudicial error do not cumulatively amount to prejudicial error.”). This court has considered, in cont