Full opinion text
Opinion GEORGE, C. J. A San Bernardino County jury found defendant Martin Carl Jennings guilty of the first degree murder of his five-year-old son, Arthur Jennings. (Pen. Code, § 187.) The jury further found true the special circumstance that the murder was intentional and involved the infliction of torture (§ 190.2, subd (a)(18)), but found not true the special circumstance that defendant intentionally killed Arthur by the administration of poison (§ 190.2, subd. (a)(19)). Following the penalty phase of the trial, the jury returned a verdict of death. After denying defendant’s motion for a new trial and his application for modification of the judgment (§ 190.4, subd. (e)), the trial court sentenced defendant to death. This appeal is automatic. (§ 1239, subd. (b).) We affirm the judgment in its entirety. I. FACTS A. Guilt Phase Evidence 1. The prosecution’s case (a) The torture and murder of Arthur Jennings Defendant was tried together with his wife, Michelle Jennings. Defendant and Michelle had been together since Michelle ran away from home in 1989, when she was 14 years of age and defendant was 29. Arthur Jennings was bom prematurely to defendant and Michelle on November 16, 1990. Shortly after Arthur’s birth, defendant and Michelle placed Arthur in the care of defendant’s mother, who soon thereafter became terminally ill. Subsequently, defendant’s half sister, Wilma S., who resided in Montana, began caring for Arthur when he was four months old. Although Arthur had several medical problems when he was bom, most seemed resolved by the time he was five years of age. In early November 1995, defendant telephoned Wilma to tell her that he wanted Arthur back. He informed Wilma that the couple had a newborn daughter, Pearl, that he had obtained employment, that the family had moved into a trailer near Apple Valley adjacent to the Mojave Desert, and that he and Michelle were prepared to raise the children together. Defendant paid for Wilma and Arthur to travel by bus from Montana to California. During Wilma’s 10-day visit, she warned defendant that Arthur wet the bed, was afraid of the dark, and could be difficult when he did not get his way. Wilma additionally told defendant and Michelle that she would take Arthur back if he proved to be too much of a problem, but she never heard from them again. When Wilma left to return to Montana, Arthur weighed approximately 64 pounds. He was happy and in good health. Within a few weeks, however, defendant and Michelle began to abuse Arthur. During late 1995 and early 1996, a number of neighbors noticed signs of abuse. Approximately two weeks before Christmas in 1995, Phillip and Kevin Grand visited the Jenningses’ home. Phillip saw Arthur with two black eyes and a mark on his mouth. Arthur was making an odd sound, rocking back and forth but staring straight ahead. When Phillip inquired what was wrong with Arthur, defendant said Michelle had “knocked him out.” Michelle confirmed to Kevin that she had “socked the damn little brat between the eyes, knocked him out.” On Christmas day in December 1995, Louis Blackwood went to the Jenningses’ residence for dinner. Blackwood saw Arthur eat two full plates of food and ask for a third, only to be reprimanded. Blackwood also noticed that Arthur’s hand was bandaged. When he asked what had happened to Arthur’s hand, Blackwood was told that Arthur had burned himself by touching the wood stove. On a separate occasion about two weeks later, Blackwood saw Arthur with a bruise on the side of his face from the hairline down to the jaw line, which Blackwood described as “not a normal injury.” Michelle told Blackwood that Arthur had fallen. Blackwood described Arthur as looking “whipped” and unhappy. In February 1996, a few days before the police started searching for Arthur, defendant told Blackwood that Arthur had gone missing in the middle of the night and that he and Michelle had spent three hours looking for Arthur before they finally found him hiding behind a bush in the desert. Bernard Romaine saw Arthur in early January 1996 and recounted that he looked “pretty beat up.” At the time, Arthur had two black eyes—one in particular that was “real bad” and appeared to require medical attention because it was swollen shut and seeping blood—and a bandaged hand that appeared to have been burned. Arthur also appeared very thin and undernourished. Pauline Morris, an acquaintance of the Jenningses’, saw Arthur in early January 1996. Arthur had bandages on his head and hands, dried blood on his face, and blood in the whites of his eyes. Defendant’s father, Art, Sr., told Morris that Arthur was injured when he fell against a wood stove. According to Morris, Arthur was very thin and, when offered milk, “swigged it down.” Morris made a report to child protective services (CPS), but CPS apparently did not follow up on the complaint. On January 5, 1996, Michelle telephoned CPS to report that her neighbors were abusing their 18-month-old son. During a subsequent telephone conversation on January 8, Michelle asked the CPS worker, Betty Hocking, if Hocking could find an adoptive home for Arthur. Michelle told Hocking that Arthur had been with them for two months and that she could not manage him. Hocking asked whether Michelle could return Arthur to the relative with whom he previously resided. Michelle responded that was not an option. Hocking then suggested parenting classes and therapy. As a last resort, she gave Michelle an adoption worker’s telephone number. On January 15, the Jenningses went to Hocking’s office to speak with her in person about the neighbors’ situation. With them was Arthur’s baby sister, Pearl, who appeared to be well taken care of and happy. At the end of the conversation, Michelle said, “I wish there was something we could do with our son,” and again inquired whether Hocking might have an adoptive home for Arthur. The Jenningses explained that they could not control Arthur and that they had many concerns about his behavior. Hocking again suggested parenting classes and therapy and gave them the adoption worker’s phone number. Before leaving, Michelle inquired whether anyone had reported the Jenningses to CPS. When asked why anyone would report them, Michelle claimed she was worried about possible allegations by jealous neighbors. On February 4, 1996, while Michelle was away, Cora Grein, a neighbor, visited the Jenningses’ home. Defendant and Arthur were watching a television program, and Grein joined them. Defendant instructed Arthur to go to his bedroom. Defendant then attempted to kiss Grein, but she resisted. During this attempt, Arthur reentered the room and subsequently was instructed by defendant to return to his bedroom. Grein testified that as Arthur began walking away, defendant grabbed him and struck him on the back of his head with a fireplace shovel. Defendant then picked up Arthur and threw him on the bed. He told Grein that if she said anything she would “see the bottom of a mine shaft.” Grein told defendant she would remain quiet, and left. Arthur died within an hour of being struck on the head with the shovel. The Jenningses initially buried Arthur’s body in a shallow grave inside an old chicken coop. A few hours later, however, they unearthed Arthur’s body and threw it down a nearby desert mine shaft. The Jenningses then attempted to scrub the blood off Arthur’s bedroom walls. Defendant also burned Arthur’s sheets and the gloves used to bury him, and placed Arthur’s diaper, clothes, and glasses in the trash. (b) The sheriffs investigation On February 6, 1996, two days after Arthur’s death, the Jenningses reported Arthur missing to the San Bernardino County Sheriff’s station. Defendant stated that he last saw Arthur in his bed at about 2:00 a.m., and noticed he was missing at 6:00 a.m. Michelle said she last saw Arthur about 10:30 p.m. Both defendant and Michelle claimed they tried to find Arthur but were unable to locate him. A search subsequently was initiated by law enforcement officers. When the search party was unable to find Arthur or any indication of recent activity by Arthur, the authorities began to treat the case as a homicide and summoned the Jenningses for questioning. In separate interviews, defendant and Michelle admitted that Arthur had been dead since February 4. They also independently led officers to the mine shaft in the desert where Arthur’s unclothed body was found wrapped in a blanket. On February 8, 1996, detectives conducted a joint interview of defendant and Michelle, in which the Jenningses detailed their abuse of Arthur. Defendant acknowledged that at various times he pushed, elbowed, kicked, shook, and hit Arthur. After initially blaming Michelle and then Grein, defendant eventually admitted striking Arthur on the back of his head with the fireplace shovel on the day he died. Defendant did state, however, that he did not want Arthur to die. Nevertheless, when later asked whether he ever had attempted to suffocate Arthur, defendant responded, “I don’t know, maybe.” During the interview, the detectives posed questions regarding incidents that had occurred prior to Arthur’s death. Defendant acknowledged he and Michelle had discussed “killing” and “getting rid of’ Arthur. Michelle said defendant wanted to shoot Arthur in the head, but she suggested returning him to Wilma or giving him to Art, Sr. Defendant admitted that two days prior to Arthur’s death, he and Michelle drove around the desert looking for a place to “dump the body.” Detectives also confronted defendant with a statement, made by defendant to Michelle, declaring that they did not need to list Arthur on their insurance policy because Arthur “wouldn’t be in the house long enough to need it.” Defendant claimed he “had a change of heart about killing [Arthur]” and that his statement had referred to the idea of returning Arthur to Wilma. The Jenningses also admitted giving Arthur the drug Unisom, an over-the-counter sleep aid, as well as Vicodin and Valium, both prescription painkillers that had been prescribed to defendant for a work-related injury. Michelle admitted that on the day Arthur died, she gave him one Vicodin and two sleeping pills at defendant’s behest, but claimed any other pills were given to Arthur by defendant. A detective asked defendant, “Did you tell her to give [Arthur] medication, that it would help him?” Defendant responded, “Yeah. I honestly thought it would. We was trying to get him better and he died.” Although acknowledging that Vicodin and Valium made defendant feel “sleepy” and “numb” and claiming that he cut the pills in halves or in quarters before giving them to Arthur, when defendant was asked what he thought the pills would do to “a five-year old that weighted] 35, 40 pounds,” defendant maintained he “didn’t think about it.” At one point during the interview, defendant acknowledged he was going “to have to pay” for what had happened to Arthur. Defendant admitted he knew he “had to finish [Arthur] off’ once Arthur saw him kissing Cora Grein. When the detectives questioned who killed Arthur, defendant stated, “I probably did” by “abusing him and the medication and stuff.” Nevertheless, defendant claimed he “did not mean to actually kill Arthur” and tried to save Arthur’s life by administering cardiopulmonary resuscitation (CPR) to him. Following defendant’s and Michelle’s arrests, officers searched their home and found, among other items, a loaded .32-caliber pistol; a fireplace shovel; a box of Unisom; and bottles of the prescription medications carisoprodol, Darvocet, Vicodin, and Valium, as well as prescription-strength ibuprofen. In the course of his testimony, a detective involved in the search showed the jury photographs of the many perishable and nonperishable food items observed in defendant’s home, and of the bloodstains found in Arthur’s bedroom. A criminologist testified that the blood spatter patterns found in 12 areas of the bedroom came from several separate events—most the result of medium-energy impact and a few from low-energy incidents and smearing. (c) The autopsy Dr. Frank Sheridan, a forensic pathologist, performed the autopsy on Arthur’s body. Dr. Sheridan testified that at the time of his death, Arthur was 3 feet 10 inches tall, and weighed only 35 pounds. His body as a whole was “severely emaciated and malnourished”; he had almost no body fat or fatty tissue, his muscles were wasted, and he had no food in his stomach when he died. Dr. Sheridan’s examination of Arthur revealed no medical reason why Arthur would not have been eating or gaining weight. The severity of Arthur’s condition indicated it was not something that had occurred over a short period of time. Dr. Sheridan also testified concerning Arthur’s numerous physical injuries, which he described as “generally painful to varying degrees” and as having required force to inflict. Visible injuries to Arthur’s body included a bruise and an abrasion on the tip of Arthur’s nose, bruising and a laceration in the area between the nose and the upper lip, bruises on the inside of his lips and gums, a lacerated oral frenulum (between the gum and the upper lip), and a slight bruise on the tip of his tongue. These injuries occurred shortly before death and were most consistent with smothering. Arthur also had two injuries to the back of his head—one injury on the right side that was a few weeks , old and had been sutured, and a second “fresh” injury on the left side that had occurred no more than six hours prior to his death, and possibly as recently as immediately preceding the time of death, but that was not itself life threatening. The remainder of Arthur’s external injuries included a severe bum on his right hand, covering half of the palm and most of the fingers, that probably was several weeks old; abrasions on his left hand and arm, right elbow, and left buttock; “mg bum” abrasions and bmising on his left back; bmises on his chest, shoulders, right elbow and arm, left arm, and left buttock; a major hemorrhage to the right shoulder blade area; and a scar on the back of his lower right thigh. An internal examination revealed extensive hemorrhaging to the deeper layers of Arthur’s scalp that extended across the entire front of his forehead, indicating some kind of blow or impact to the area. This injury occurred shortly before Arthur’s death but separately from his other recent head injury. Arthur also had a subdural hemorrhage on the left side of his head that was at least 10 days old, and hemorrhaging around the optic nerves of the back of the eyes from the same injuring event. Dr. Sheridan referred to this as an “acceleration/deceleration injury” consistent with a child who had been shaken violently, possibly causing permanent brain damage. A microscopic examination of Arthur’s lung tissue indicated he had acute pneumonia at the time of his death. Dr. Sheridan attributed this infection to the breakdown of Arthur’s immune system and his overall failure to thrive. Toxicology tests revealed that Arthur had three drugs in his blood system, all central nervous system depressants. The first drug was a significant amount of Unisom consistent with the administration of two sleeping pills. The dose was sufficient to cause seizures and cessation of breathing. The second drug was a small amount of Vicodin, a prescription painkiller, which would have added to the sedative or depressive effect of the Unisom. The third drug was a small amount of Valium, which would have played a minor contributing role in Arthur’s condition. When asked whether he had determined “a cause of death or causes of death,” Dr. Sheridan replied, “Causes.” On the death certificate, he listed the “main cause of death” as “combined drug toxicity,” because although the level of Unisom alone was potentially fatal and the levels of Vicodin and Valium alone were not toxic, the three drugs together had a certain “additive effect” on sedation. Under the heading “Contributing Causes”—which Dr. Sheridan explained is “where you can list something else that contributed to death but is separate from the main one”—he listed “acute and chronic physical abuse and neglect.” The term “acute” referred to Arthur’s injuries inflicted shortly before death, and the term “chronic” referred to Arthur’s older injuries as well as to the “very, very severe” emaciation and malnutrition. Also listed as a contributing cause was the acute pneumonia, which was a complication of Arthur’s emaciated state. Questioned further, Dr. Sheridan gave the cause of death as “the entire problem”—the drugs, the physical injuries, and the malnutrition and emaciation—“all working together,” that brought about the resulting death. He described Arthur as in a “downhill slide” and “very near to the end of his life” because of malnutrition and “the whole body not functioning properly.” Dr. Sheridan testified that even without the ingestion of drugs, Arthur likely would have died within a fairly short period of time if he were not given medical attention and food. Without the positive toxicology results, Dr. Sheridan would have concluded that acute abuse was the primary cause of death, most likely by smothering. (d) Stipulation regarding expert toxicologist The parties entered into a stipulation concerning the testimony of Dr. Randall C. Baselt, a toxicologist, which was read into the record. According to the stipulation, if called as a witness Baselt would have testified that the drug concentrations found in the autopsy blood specimen of five-year-old, 35-pound Arthur Jennings, “when taken at face value, were sufficient to account for [his] death.” The Unisom “played the most important role in this drug combination, and, in fact, could have caused death in the absence of the other two agents.” He noted, however, that without analyzing other autopsy specimens, such as liver, brain, urine or stomach contents, “it would be difficult for a forensic toxicologist to offer any definitive opinions as to the timing of the drug administration, the size of the dose or doses and the exact role that the [Unisom] played in the death.” 2. The defense’s case Neither defendant nor Michelle testified at trial. Defendant called Dr. Joseph Lantz, a licensed clinical psychologist, who testified concerning the results of tests he administered to determine defendant’s cognitive ability, intelligence, and personality profile. Lantz opined that defendant possessed limited intelligence, was severely impaired in his problem-solving ability, had a personality disorder consisting of narcissism and antisocial behavior, and had been abused by his parents. Lantz further explained that a person who is severely abused as a child is much more at risk as an adult to perpetuate a pattern of abuse. He concluded that defendant was angry, hostile, explosive, impulsive, and difficult to deal with. Additionally, Lantz noted that defendant’s personality problems increased when he lost his job due to a back and shoulder injury. Defendant was in pain, not working, and short of money. When defendant was employed, he was a regular methamphetamine user, but later quit. As Lantz explained, those who quit use of that drug “generally go through a period of agitation.” Defendant stopped using methamphetamine when he developed nausea due to the interaction between the methamphetamine and his prescription medications. Lantz further testified that the Jenningses had no concept of how to deal with Arthur’s needs. He also opined that Arthur’s behavior had deteriorated to that of a child of lesser age after he was returned to his parents’ care, and that the Jenningses responded by reverting to the disciplinary techniques that had been used upon them. Lantz concluded, however, “that things had gone so far out of line that even [defendant] and Michelle could understand that. . . they needed to do something to help the child.” Lantz believed the Jenningses gave Arthur pills to “provide some mercy to the child.” In Lantz’s opinion, in light of the circumstance that “[the Jenningses] were not holding back” when they abused Arthur, defendant demonstrated some restraint by administering only two pills to Arthur. He acknowledged, however, that defendant lacked empathy and that neither defendant nor Michelle seemed to care about Arthur’s death. Michelle called Dr. Nancy Kaser-Boyd, a licensed clinical psychologist, who testified concerning her testing and evaluation of Michelle. The psychologist related Michelle’s history of rape and abuse by her father (resulting in pregnancy and an abortion), betrayal by an older sister and her mother, molestation by a teacher, and abuse by defendant. Kaser-Boyd stated that Michelle was fearful, depressed, and lacked insight, was socially isolated and felt helpless, had difficulty controlling her impulses, had a dependent and schizophrenic personality, and possessed an IQ in the bottom fifth percentile. Kaser-Boyd explained that the characteristics displayed by Michelle are typical of abused and battered women. Kaser-Boyd further testified that Michelle did not understand Arthur’s seizures—which defendant told her were temper tantrums but Kaser-Boyd, based on her own experience and training, viewed as epileptic—and that Michelle’s response to the seizures was to slap Arthur. Kaser-Boyd explained that Michelle wanted to obtain medical care for Arthur, but did not do so because he had bruises and she was afraid of losing custody of her baby, Pearl. Michelle also told Kaser-Boyd that defendant suggested withholding food from Arthur because hitting him “was not working,” and that Michelle went along with defendant’s plan, but sometimes would sneak food to Arthur. An adoption social worker, Margret Thomas, testified regarding a telephone call she received on January 18, 1996, from Michelle discussing adoption options for Arthur. During the call, Michelle said Arthur was recently returned to her home, but she was unable to handle him and therefore was considering placing him for adoption. By the end of the conversation, Michelle agreed to consider returning Arthur to Wilma, the paternal aunt with whom he had resided in Montana before being returned to the Jenningses. Michelle never followed up with Thomas. 3. The prosecution’s rebuttal Sheriff’s investigator Kathleen Cardwell interviewed Michelle on February 6, 1996, and asked her about her relationship with defendant. Michelle responded that she had an excellent relationship with him, stating they got along fine and defendant treated her well. When Cardwell inquired whether defendant ever physically abused her, Michelle said he hit her when they first married. She had threatened to leave him, and since 1990 he never struck or mistreated her again. Cardwell did not notice any visible injuries on Michelle. B. Penalty Phase Evidence 1. The defense’s case Dr. Geraldine Stahly, a social psychologist, testified concerning the history of defendant’s family. Most of defendant’s relatives suffered from mental illness and low intelligence, many had criminal histories, and two half brothers were in prison for murder, one on death row. Defendant’s mother, Pearl Jennings, was reported to have suffered from heroin addiction and at some point to have been placed in a mental hospital for schizophrenia. She had 11 children with her first husband, Raymond Foster. The Foster children were sexually abused by their father and physically abused by both parents. Later, however, the Foster sons came to idealize their father because they “remembered him as not being so bad.” The Foster children also were sexually molested and physically abused by their mother’s second husband, Art, Sr., who was defendant’s biological father. Art, Sr., allegedly killed Helen, one of the Foster children, by smothering her with a pillow when she was five years of age. In 1957, after approximately two years together, the Foster children, as well as Pearl and Art’s newborn baby, were taken from them by the state. The baby was adopted, and the other children were placed in foster homes and orphanages. Defendant was bom in 1960. He was much younger than the Foster children and was raised as if he were an only child. At that time, the economic circumstances of the Jennings family had improved considerably. Art, Sr., once forced defendant to steal but subsequently did not press him to engage in such activity again, because defendant proved to be an inept thief. The Foster children perceived that defendant was “spoiled” and “had it good.” But defendant reported to Stahly that his mother forced him to orally copulate her when defendant was nine years of age and demanded during the ensuing year that he perform this act a couple of times a week. He also told Stahly that before attaining the age of 13 years, he was forced to orally copulate Art’s girlfriend. Both parents also physically abused defendant, although apparently not to the extent they abused the Foster children. In Stahly’s opinion, defendant and his siblings suffered not only from sexual and physical abuse, but also from emotional and “moral” abuse. Stahly discussed various factors that placed Arthur at risk for being abused when he was returned to defendant’s care. She stated that violence was defendant’s way of coping with stress and that he “never saw any other coping style.” According to Stahly, individuals are “children of [their] parents” and parents will shape the lives of their children absent outside intervention, which did not occur in defendant’s case. Stahly also acknowledged, however, that if victims are able to recognize that their experiences and patterns of behavior are abnormal, they can end the cycle of abuse as they mature. Joseph Lantz, the psychologist who testified on defendant’s behalf at the guilt phase of the trial, testified again at the penalty phase. In Lantz’s opinion, defendant was seriously affected by the environment in which he was raised. Lantz agreed with Stahly’s testimony, adding that there would have to be “very active intervention both with the child and with the family” for someone who had been seriously damaged by abuse as a child “to turn their life around.” Lantz stated that social isolation, coupled with severe and ongoing physical, emotional, and sexual abuse and neglect, left defendant “to drift” without normal development. Lantz referred to an incident in which defendant’s arm was broken when his father attacked him with a baseball bat, and another event when defendant was shot during a hunting accident and his father tied him down at home while removing the bullet fragments. Lantz also testified that defendant was incapable of deciding to take Arthur’s life and did not intend to kill Arthur. James Park, a retired employee of the California Department of Corrections, testified regarding the situation defendant would encounter if sentenced to life imprisonment without the possibility of parole. In Park’s opinion, defendant was unlikely to be a danger to anyone inside the prison. 2. The prosecution’s case The prosecution presented one rebuttal witness, defendant’s half sister, F.E., who testified that she was sexually and physically abused by her father, Raymond Foster. Her mother Pearl, whom F.E. described as cold and distant, was not abusive, although Pearl knew about the abuse and did nothing to stop it. F.E. ran away and in 1954 was placed in a home for girls. Nevertheless, F.E. saw Pearl and Art, Sr., on various occasions. In 1960, F.E. visited her mother, who was pregnant with defendant, but left after Art, Sr., beat and raped her. She again visited her mother and Art for approximately six weeks in 1971, when defendant was 10 or 11 years of age. On that occasion, she observed that Pearl adored defendant and Art was very good to him. Beginning in 1973, F.E. saw the family regularly and observed normal parent-child relationships between defendant and his parents. Wilma S., defendant’s half sister who raised Arthur until he was five years of age, testified again at the penalty phase as a victim-impact witness. Wilma explained that she was given custody of Arthur when he was four and a half months old and that she loved him very much. She had not wanted to return Arthur to defendant and Michelle, but when she sought legal advice, she was told she could not keep him. Wilma further testified that although Art, Sr., sexually molested her and physically abused her and all of her siblings, her mother did not beat her. II. DISCUSSION A. Guilt Phase Issues 1. Sufficiency of the evidence Defendant contends that the evidence presented at the guilt phase was insufficient to establish first degree murder or the torture-murder special circumstance. He further asserts that basing a conviction or special circumstance finding on the insufficient evidence presented at his trial violated the “narrowing” principle of the Fifth, Eighth, and Fourteenth Amendments of the United States Constitution and his right to due process of law under the Fifth and Fourteenth Amendments. The law governing sufficiency-of-the-evidence challenges is well established and applies both to convictions and special circumstance findings. (People v. Valdez (2006) 32 Cal.4th 73, 104 [8 Cal.Rptr.3d 271, 82 P.3d 296]; People v. Elliot (2005) 37 Cal.4th 453, 466 [35 Cal.Rptr.3d 759, 122 P.3d 968] (Elliot).) In reviewing a claim for sufficiency of the evidence, we must determine whether, after viewing the evidence in the light most favorable to the prosecution, any rational trier of fact could have found the essential elements of the crime or special circumstance beyond a reasonable doubt. We review the entire record in the light most favorable to the judgment below to determine whether it discloses sufficient evidence—that is, evidence that is reasonable, credible, and of solid value—supporting the decision, and not whether the evidence proves guilt beyond a reasonable doubt. (People v. Mincey (1992) 2 Cal.4th 408, 432 [6 Cal.Rptr.2d 822, 827 P.2d 388].) We neither reweigh the evidence nor reevaluate the credibility of witnesses. (People v. Lindberg (2008) 45 Cal.4th 1, 27 [82 Cal.Rptr.3d 323, 190 P.3d 664].) We presume in support of the judgment the existence of every fact the jury reasonably could deduce from the evidence. (Ibid.) If the circumstances reasonably justify the findings made by the trier of fact, reversal of the judgment is not warranted simply because the circumstances might also reasonably be reconciled with a contrary finding. (Ibid.) In the present case, the trial court instructed the jury concerning three alternative theories of first degree murder advanced by the prosecution— murder by poison, murder by torture, and premeditated murder—and the verdict does not specify which theory the jury relied upon in finding defendant guilty. “A jury may convict a defendant of first degree murder, however, without making a unanimous choice of one or more of several theories proposed by the prosecution . . . .” (People v. Beardslee (1991) 53 Cal.3d 68, 92 [279 Cal.Rptr. 276, 806 P.2d 1311].) As we explain below, the record discloses sufficient evidence to support the jury’s finding that defendant was guilty of first degree murder on each of these three theories. There also is sufficient evidence to support the torture-murder special-circumstance finding. Because defendant’s corresponding constitutional claims rely upon the alleged insufficiency of the evidence and related arguments that we reject, they necessarily must fail as well. (a) Sufficiency of the evidence to establish first degree murder by poison Defendant contends he could not have been convicted of first degree murder by poison, because the jury found the poison-murder special circumstance “not true,” and because Michelle, not defendant, administered “the fatal poison” and there is “no evidence” she intended to kill Arthur. We disagree. Reviewing the record in the light most favorable to the judgment, there is ample evidence to support defendant’s first degree murder conviction on the basis of murder by poison. As we previously have noted, “it is not the case that the elements of the murder-by-poison special circumstance merely repeat the elements that render a homicide a first degree murder when committed by means of poison.” (People v. Catlin (2001) 26 Cal.4th 81, 158 [109 Cal.Rptr.2d 31, 26 P.3d 357] (Catlin)-, see § 189 [“All murder which is perpetrated by means of . . . poison ... is murder of the first degree.”]; § 190.2, subd. (a)(19) [defining the poison-murder special circumstance as a first degree murder in which “[t]he defendant intentionally killed the victim by the administration of poison”].) “The special circumstance allegation, unlike the definition of first degree murder by poison, requires proof that the defendant intentionally killed the victim. For the purpose of a first degree murder conviction based upon an unlawful killing by means of poison, proof of implied malice would suffice . . . .” (Catlin, supra, 26 Cal.4th at p. 158.) Therefore, even if we were to assume the jury rejected the murder-by-poison special circumstance because it was not persuaded beyond a reasonable doubt that either defendant or Michelle intended to kill Arthur by means of the drugs, the jury still could have reasonably found defendant guilty of first degree murder by poison if it found that either codefendant acted with implied malice. (People v. Diaz (1992) 3 Cal.4th 495, 568 [11 Cal.Rptr.2d 353, 834 P.2d 1171] [“A defendant acting with implied malice who kills his or her victim with poison is guilty of first degree murder even if the defendant lacks the intent to kill.”].) The trial court instructed the jury pursuant to CALJIC No. 8.11 concerning implied malice, as follows; “Malice is implied when: [][] 1. The killing resulted from an intentional act; [f] 2. The natural consequences of the act are dangerous to human life; and [f] 3. The act was deliberately performed with knowledge of the danger to, and with conscious disregard for, human life.” Defendant does not dispute that the natural consequences of administering three powerful sedatives to a five-year-old child are dangerous to human life, or that furnishing the drugs to Arthur was a cause of his death. The only issue in terms of implied malice, therefore, is whether there was sufficient evidence for a reasonably jury to have found that defendant “ ‘had full knowledge that his conduct endangered the life of decedent, but that he nevertheless deliberately administered the poison with conscious disregard for that life.’ [Citation.]” (People v. Blair (2005) 36 Cal.4th 686, 745 [31 Cal.Rptr.3d 485, 115 P.3d 1145].) The evidence presented at trial reasonably established the following sequence of events. On the morning of February 4, 1996, defendant directed Michelle to go to the store to purchase over-the-counter sleeping pills to give to Arthur. When she returned, Michelle gave Arthur two Unisom sleeping pills, as well as one Valium, at defendant’s direction. Defendant gave. Arthur additional pain pills, which included Vicodin. Arthur died later that day as a result of combined drug toxicity and acute and chronic abuse and neglect. A box of Unisom sleeping pills in child-resistant packaging found at defendant’s home was entered into evidence. In response to a juror question, the instructions on the back of the package were read out loud by Dr. Sheridan. The instructions indicated that the proper adult dosage was one tablet daily and warned in pertinent part: “Do not take this product if presently taking any other drug without consulting your physician or pharmacist. . . . For adults only. Do not give to children under age twelve years. Keep this and all medications out of the reach of children.” (Italics added.) Multiple child-proof containers of Vicodin and Valium that had been prescribed to defendant also were entered into evidence and shown to the jury. In the joint interview, defendant altered his story several times and admitted lying to the detectives on numerous occasions. In evaluating the evidence pertaining to poisoning, the jury was not required to accept, and was entitled to reject, the claims that defendant administered the drugs to Arthur in an effort “to get him better,” that defendant did not “know much” about the drugs, and that he “didn’t think” about what effect the drugs would have on Arthur. To the contrary, the jury could have inferred exactly the opposite from defendant’s remarks about killing Arthur, the acknowledgement that Vicodin and Valium made defendant feel “sleepy” and “numb,” his claim that he halved or quartered the prescription pain pills before giving them to Arthur, and the admission by defendant that he “probably” killed Arthur by “[abusing him and the medication and stuff like that.” This evidence was sufficient for a reasonable jury to find that defendant deliberately administered the drugs to Arthur, and directed Michelle to do the same, with full knowledge that such conduct endangered Arthur’s life and with conscious disregard for that life. Defendant attempts to parse his involvement from Michelle’s role in the administration of the drugs, ignoring the circumstance that he was charged and tried as an aider and abettor, as well as a direct perpetrator. “Aider and abettor liability is premised on the combined acts of all the principals, but on the aider and abettor’s own mens rea. If the mens rea of the aider and abettor is more culpable than the actual perpetrator’s, the aider and abettor may be guilty of a more serious crime than the actual perpetrator. [f] Moreover, the dividing line between the actual perpetrator and the aider and abettor is often blurred. It is often an oversimplification to describe one person as the actual perpetrator and the other as the aider and abettor. When two or more persons commit a crime together, both may act in part as the actual perpetrator and in part as the aider and abettor of the other, who also acts in part as an actual perpetrator.” (People v. McCoy (2001) 25 Cal.4th 1111, 1120 [108 Cal.Rptr.2d 188, 24 P.3d 1210].) The evidence described above was sufficient for a reasonable jury to have found that defendant poisoned Arthur, or that he aided and abetted Michelle in poisoning Arthur, or that both occurred. Therefore, even assuming for purposes of argument that the sleeping pills administered by Michelle were the sole cause of Arthur’s death, and that the additional drugs and torture were not concurrent causes, a reasonable jury still could have found defendant guilty of first degree murder by poison as an aider and abettor. In any event, there is sufficient evidence to support defendant’s conviction of first degree murder on the theory of murder by poison. (b) Sufficiency of the evidence to establish first degree murder by torture Defendant claims the evidence was insufficient to support his conviction of first degree murder on a murder-by-torture theory. (See § 189 [“All murder which is perpetrated by means of . . . torture ... is murder of the first degree.”].) He does not contend that the evidence of his physical abuse of Arthur—which included burning Arthur’s hand on the stove, giving him black eyes, hitting him with a two-by-four, violently shaking and banging Arthur’s head against the wall, kicking him in the midsection, duct-taping his mouth and hands, smothering him, and hitting Arthur in the back of the head with a fireplace shovel—was insufficient to establish torture. Rather, defendant contends that even assuming he tortured Arthur, there is insufficient evidence that his torture was the “but for” cause of Arthur’s death, which defendant attributes to the drugs. We disagree. There was sufficient evidence presented at trial from which a reasonable juror could have found that defendant’s acts of physical violence and deliberate starvation of Arthur were concurrent causes of Arthur’s death. As such, the evidence is sufficient to support a conviction of first degree murder by torture. The elements of first degree murder by torture are: “(1) acts causing death that involve a high degree of probability of the victim’s death; and (2) a willful, deliberate, and premeditated intent to cause extreme pain or suffering for the purpose of revenge, extortion, persuasion, or another sadistic purpose. [Citations.]” (People v. Cook (2006) 39 Cal.4th 566, 602 [47 Cal.Rptr.3d 22, 139 P.3d 492].) The prosecution need not establish that the defendant intended to kill the victim (ibid.), but must prove a causal relationship between the torturous acts and the death (People v. Chatman (2006) 38 Cal.4th 344, 392 [42 Cal.Rptr.3d 621, 133 P.3d 534] (Chatman)). “The finding of murder-by-torture encompasses the totality of the brutal acts and the circumstances which led to the victim’s death. [Citations.] The acts of torture may not be segregated into their constituent elements in order to determine whether any single act by itself caused the death; rather, it is the continuum of sadistic violence that constitutes the torture.” (People v. Proctor (1992) 4 Cal.4th 499, 530-531 [15 Cal.Rptr.2d 340, 842 P.2d 1100].) If a defendant’s acts of torture were a concurrent cause of the death, it is no defense that the conduct of some other person contributed to the death. “ ‘ “When the conduct of two or more persons contributes concurrently as the proximate cause of the death, the conduct of each is a proximate cause of the death if that conduct was also a substantial factor contributing to the result. A cause is concurrent if it was operative at the time of the death and acted with another cause to produce the death.” ’ [Citation.]” (People v. Sanchez (2001) 26 Cal.4th 834, 847 [111 Cal.Rptr.2d 129, 29 P.3d 209]; see also 1 Witkin & Epstein, Cal. Criminal Law (3d ed. 2000) Elements, § 37, p. 243 [“The defendant may also be criminally liable for a result directly caused by his or her act, even though there is another contributing cause.”].) “To be considered the proximate cause of the victim’s death, the defendant’s act must have been a substantial factor contributing to the result, rather than insignificant or merely theoretical.” (People v. Briscoe (2001) 92 Cal.App.4th 568, 583-584 [112 Cal.Rptr.2d 401].) “[A]s long as the jury finds that without the criminal act the death would not have occurred when it did, it need not determine which of the concurrent causes was the principal or primary cause of death.” (Catlin, supra, 26 Cal.4th at p. 155.) For this reason, defendant’s focus upon “but for” causation, and whether the drugs were the “primary cause” of Arthur’s death, is misplaced. “But for” or “sine qua non” causation provides that “[t]he defendant’s conduct is a cause of the event if the event would not have occurred but for that conduct; conversely, the defendant’s conduct is not a cause of the event, if the event would have occurred without it.” (Prosser & Keeton, Torts (5th ed. 1984) § 41, p. 266, fn. omitted.) By comparison, the “substantial factor” rule for concurrent causes “was developed primarily for cases in which application of the but-for rule would allow each defendant to escape responsibility because the conduct of one or more others would have been sufficient to produce the same result.” (Prosser & Keeton, at p. 268.) As we have stated in the civil context, the tests for “but for” and “substantial factor” causation usually produce the same result, but the “substantial factor” standard states a clearer rule that subsumes and reaches beyond the “but for” test to more accurately address situations in which there are independent concurrent causes of an event. (Lineaweaver v. Plant Insulation Co. (1995) 31 Cal.App.4th 1409, 1415 [37 Cal.Rptr.2d 902]; see also Viner v. Sweet (2003) 30 Cal.4th 1232, 1239-1240 [135 Cal.Rptr.2d 629, 70 P.3d 1046].) In the present case, there was sufficient evidence from which a reasonable jury could have concluded that defendant’s torture was at least a substantial factor in Arthur’s death. Dr. Sheridan testified that the cause of Arthur’s death was attributable to “the entire problem”—that it, the drugs, the physical injuries, and the malnutrition and emaciation—“all working together to bring about the resulting death. (Italics added.) Additionally, the expert toxicologist and Dr. Sheridan both concluded that the dosage of Unisom that was administered to Arthur was sufficient to account for Arthur’s death in light of his age and weight. The jury reasonably could have inferred from this evidence that defendant’s physical abuse and purposeful starvation of Arthur contributed to the lethal effect of the pills, and therefore was a substantial factor in his death. Defendant contends, however, that the jury could not properly consider starvation as an aspect of torture, because there was insufficient evidence that defendant deliberately withheld nourishment from Arthur. We disagree. Wilma S., Arthur’s aunt, testified that when she returned Arthur to his parents in November 1995, he weighed 64 pounds and was in good health. In the weeks leading up to his death, neighbors reported that Arthur appeared thin and undernourished, despite the circumstance that the Jenningses had ample food in their home. When offered food or drink, Arthur “gulped” it down and asked for additional portions, suggesting he had not eaten recently. When he died on February 4, 1996, Arthur weighed only 35 pounds, having lost nearly half of his body weight in less than three months. Dr. Sheridan, who conducted the autopsy, testified that Arthur’s body had almost no fat beneath the skin, had broken down muscle tissue for energy, and lacked food in the stomach at the time of death. Arthur also suffered from acute pneumonia and from a breakdown of his immune system due to emaciation. The jury was shown photographs of Arthur taken between November 1995 and February 1996, including some taken at the autopsy, which demonstrated his decline. Dr. Sheridan further testified there was no medical reason for Arthur’s dramatic weight loss over this short a period of time. The foregoing constitutes substantial evidence from which the jury reasonably could find that the Jenningses deliberately starved Arthur. This evidence, along with the evidence of chronic and acute physical abuse, is sufficient to support defendant’s first degree murder conviction on the basis of murder by torture. (c) Sufficiency of the evidence to establish first degree premeditated murder Defendant contends that he was improperly convicted of first degree premeditated murder, because there is “no evidence” he killed Arthur by means of a deliberate and premeditated act. (See § 189 [“All murder which is perpetrated ... by any other kind of willful, deliberate, and premeditated killing ... is murder of the first degree.”].) As demonstrated above in response to defendant’s claims related to murder by torture and murder by poison, however, there is sufficient evidence from which the jury reasonably could have found that defendant caused Arthur’s death. Additionally, as demonstrated below in response to defendant’s torture-murder special-circumstance claim, there is sufficient evidence from which the jury could have found that defendant intended to kill Arthur. The only remaining question for purposes of the present claim is whether there is sufficient evidence of deliberation and premeditation. “An intentional killing is premeditated and deliberate if it occurred as the result of preexisting thought and reflection rather than unconsidered or rash impulse.” (People v. Stitely (2005) 35 Cal.4th 514, 543 [26 Cal.Rptr.3d 1, 108 P.3d 182].) In this context, “ ‘premeditated’ means ‘considered beforehand,’ and ‘deliberate’ means ‘formed or arrived at or determined upon as a result of careful thought and weighing of considerations for and against the proposed course of action.’ ” (People v. Mayfield (1997) 14 Cal.4th 668, 767 [60 Cal.Rptr.2d 1, 928 P.2d 485].) We normally consider three kinds of evidence to determine whether a finding of premeditation and deliberation is adequately supported—preexisting motive, planning activity, and manner of killing—but “[t]hese factors need not be present in any particular combination to find substantial evidence of premeditation and deliberation.” (Stitely, supra, at p. 543.) If the evidence of preexisting motive and planning activity by itself is sufficient to support the first degree murder conviction on a theory of premeditation and deliberation, we need not review the evidence concerning the manner of killing. (People v. Jurado (2006) 38 Cal.4th 72, 119 [41 Cal.Rptr.3d 319, 131 P.3d 400].) In the case before us, the evidence of preexisting motive clearly supports a finding of premeditation and deliberation. After returning to the Jennings residence, Arthur soon proved to be a difficult child with significant problems, and defendant and Michelle quickly found themselves ill-equipped to handle Arthur’s “fits” and were unable to manage or control his behavior. Although Wilma S. clearly had said she would take Arthur back at any time, defendant did not pursue this option, nor did he pursue the course of giving Arthur up for adoption. Instead, he attempted to “discipline” Arthur by inflicting repeated physical punishment that left Arthur’s body covered in bruises, and by purposefully withholding food to the extent that Arthur lost nearly half his body weight in less than three months. The situation quickly deteriorated to the point that defendant spoke about “getting rid of,” “shooting,” or otherwise “killing” Arthur. The evidence of planning activity also supports a finding of premeditation and deliberation. On the day Arthur was killed but before he was dead, Michelle and Art, Sr., went out at defendant’s behest to survey the mine shaft where Arthur later was found. Two days before Arthur’s death, defendant and Michelle had driven around the desert looking for a place to dump Arthur’s body. A few days before that, defendant devised the story he later would use to explain Arthur’s disappearance, telling a neighbor that Arthur got up in the middle of the night and ran out into the desert, and that defendant and Michelle had spent three hours looking for Arthur before finding him hiding behind a bush. After killing Arthur, the Jenningses went to the sheriff’s station with a similar story, claiming that Arthur had run away in the middle of the night. Moreover, in the days leading up to Arthur’s death, defendant refused to add Arthur to the family’s medical insurance policy, stating, “he wouldn’t be in the house long enough to need it.” Finally, the manner of killing supports the conclusion that Arthur’s death was the result of preexisting thought and reflection rather than unconsidered or rash impulse. Arthur was systematically starved and continuously abused, and a potentially lethal dose of prescription and over-the-counter sedatives was deliberately administered. This conduct is entirely consistent with a preconceived design to kill, and the jury was not required to accept defendant’s claims to the contrary. In light of the foregoing, we conclude the evidence presented at trial was sufficient for a reasonable jury to have found that the killing of Arthur was premeditated and deliberate. As such, there is sufficient evidence to support defendant’s first degree murder conviction on the basis of premeditated murder. (d) Sufficiency of the evidence to establish the torture-murder special circumstance Defendant claims there is insufficient evidence to support the jury’s torture-murder special-circumstance finding. Reviewing the entire record in the light most favorable to the prosecution, we conclude a rational trier of fact could have found true beyond a reasonable doubt the essential elements of the torture-murder special-circumstance allegation. Under the applicable statute, first degree murder is punishable by death or life in prison if the murder “was intentional and involved the infliction of torture.” (§ 190.2, subd. (a)(18).) Proof of a murder committed under the torture-murder special circumstance requires (1) proof of first degree murder, (2) proof that the defendant intended to kill and torture the victim, and (3) proof of the infliction of an extremely painful act upon a living victim. (People v. Davenport (1985) 41 Cal.3d 247, 271 [221 Cal.Rptr. 794, 710 P.2d 861].) The torture-murder special circumstance thus is distinguished from first degree murder by torture in that it requires defendant to have acted with the intent to kill and applies where the death involved the infliction of torture, regardless of whether the acts constituting the torture were the cause of death. (See § 190.2, subd. (a)(18); People v. Bemore (2000) 22 Cal.4th 809, 842-843 [94 Cal.Rptr.2d 840, 996 P.2d 1152] (Bemore).) Defendant, focusing entirely on Michelle’s allegedly innocuous intent in giving Arthur the sleeping pills, argues there was insufficient evidence of his intent to kill. The relevant inquiry, however, is whether defendant harbored an intent to kill when he tortured Arthur. The nature of the torture inflicted upon Arthur—the continuous infliction of serious and possibly life-threatening physical injuries while deliberately and systematically starving Arthur to the point of emaciation—is sufficient to suggest that defendant had such intent. In evaluating the evidence regarding intent to kill, the jury was not required to credit, and was entitled to reject, defendant’s repeated claims to the contrary. Defendant admitted that one of his last acts of torture—hitting Arthur on the back of the head with a shovel so hard that it caused a large, gaping wound—might have killed Arthur, suggesting this was his intent. Defendant also admitted he was “more than angry” that Arthur had witnessed defendant kissing a neighbor, and when asked by a detective, “You had to finish him off. True or not true?,” defendant responded, “I guess true.” The evidence further established that prior to the incident involving the shovel, defendant on more than one occasion spoke about killing Arthur, kept him off the family’s medical plan “because he wouldn’t be in the house long enough to use it,” searched the desert for a place to dispose of Arthur’s body two days before his death, and went to great lengths to conceal Arthur’s death, including planning the “runaway” story he would tell the authorities. This evidence is sufficient to support a finding, in connection with the torture-murder special circumstance, that defendant intended to kill Arthur. Defendant also argues there is insufficient evidence that Arthur’s murder “involved the infliction of torture.” (§ 190.2, subd. (a)(18).) In resolving above the claim by defendant that the evidence was insufficient to sustain his conviction of first degree murder under a theory of murder by torture, we found sufficient evidence to establish that the torture perpetrated by defendant was a concurrent cause of Arthur’s death. Unlike first degree murder by torture, however, the special circumstance does not require that the acts constituting the torture cause the death. (Bemore, supra, 22 Cal.4th at p. 843.) Rather, “ ‘some proximity in time [and] space between the murder and torture’ ” will suffice. (Ibid.) Whatever the “ ‘outer limits’ ” of the torture-murder special circumstance might be in this regard, the proximity requirement is satisfied when the acts of torture also were a cause of death. (Chatman, supra, 38 Cal.4th at p. 394.) Even absent the evidence of concurrent causation, the record in this case discloses a “close connection between the torture and the murder.” (Bemore, supra, 22 Cal.4th at p. 843.) Arthur had received several “fresh” injuries—including the head wound defendant admitted to inflicting with a shovel and the facial injuries consistent with a smothering attempt—shortly before his death. Finally, defendant argues that the torture-murder special circumstance is unconstitutional because the acts of torture are not required to be the sole or primary cause of the victim’s death. As he acknowledges, however, we previously have rejected this argument. (Bemore, supra, 22 Cal.4th at p. 843.) We find no compelling reason to revisit the issue. (e) Constitutional challenges to sufficiency of the evidence Defendant claims that even if there is sufficient evidence to support his conviction for first degree murder, the conviction violates his rights under the Fifth, Eighth, and Fourteenth Amendments of the United States Constitution. We conclude that the jury’s first degree murder verdict did not violate any of defendant’s constitutional rights. Defendant argues that his first degree murder conviction makes him “death eligible” in a case in which he did not cause the death and the death was unintentional, in violation of the principle that a state’s death penalty scheme must meaningfully narrow the class of persons eligible for the death penalty. (See, e.g., Zant v. Stephens (1983) 462 U.S. 862 [77 L.Ed.2d 235, 103 S.Ct. 2733]; Beck v. Alabama (1980) 447. U.S. 625 [65 L.Ed.2d 392, 100 S.Ct. 2382]; Godfrey v. Georgia (1980) 446 U.S. 420 [64 L.Ed.2d 398, 100 S.Ct. 1759]; Lockett v. Ohio (1978) 438 U.S. 586 [57 L.Ed.2d 973, 98 S.Ct. 2954]; Gardner v. Florida (1977) 430 U.S. 349 [51 L.Ed.2d 393, 97 S.Ct. 1197].) This argument fails for three reasons. First, there is sufficient evidence, as outlined above, from which a rational trier of fact could have found beyond a reasonable doubt that the torture inflicted by defendant caused Arthur’s death. Second, we have held that imposition of the death penalty upon one who lacks the intent to kill is not cruel and unusual punishment in violation of the Eighth Amendment. (See, e.g., People v. Diaz, supra, 3 Cal.4th at p. 569; see also Tison v. Arizona (1987) 481 U.S. 137, 157-158 [95 L.Ed.2d 127, 107 S.Ct. 1676].) Third, it was defendant’s first degree murder conviction in conjunction with the jury’s time finding on the torture-murder special circumstance—which required an intent to kill—that ultimately made defendant eligible for the death penalty. The United States Supreme Court has held that California’s requirement of a special circumstance finding adequately “limits the death sentence to a small subclass of capital-eligible cases.” (Pulley v. Harris (1984) 465 U.S. 37, 53 [79 L.Ed.2d 29, 104 S.Ct. 871].) More specifically, we have held that “[t]he special circumstance of intentional murder involving the infliction of torture sufficiently channels and limits the jury’s sentencing discretion consistent with Eighth Amendment principles [citation], and meaningfully narrows the group of persons subject to the death penalty [citations].” (People v. Barnett (1998) 17 Cal.4th 1044, 1162-1163 [74 Cal.Rptr.2d 121, 954 P.2d 384]; see also People v. Raley (1992) 2 Cal.4th 870, 900 [8 Cal.Rptr.2d 678, 830 P.2d 712] [torture murder is “particularly reprehensible because the defendant intends to cause cmel suffering”].) Defendant next argues that any interpretation of the evidence in this case that renders him guilty of first degree murder violates the well-settled constitutional principle prohibiting punishment determined under vague, arbitrary, or illegitimate standards. (See, e.g., Kolender v. Lawson (1983) 461 U.S. 352, 357 [75 L.Ed.2d 903, 103 S.Ct. 1855]; Hicks v. Oklahoma (1980) 447 U.S. 343, 346 [65 L.Ed.2d 175, 100 S.Ct. 2227].) The existence of substantial evidence from which a rational trier of fact could find beyond a reasonable doubt the essential elements of first degree murder, as well as the torture-murder special circumstance, satisfies the due process clause of the United States Constitution, as well as its counterpart in article I, section 15 of the California Constitution. (See Jackson v. Virginia (1979) 443 U.S. 307, 318-319 [61 L.Ed.2d 560, 99 S.Ct. 2781]; People v. Berryman (1993) 6 Cal.4th