Penal Code Section 189 makes a murder perpetrated by means of torture a murder of the first degree. 'Murder by torture "is 'murder committed with a willful, deliberate and premeditated intent to inflict extreme and prolonged pain. ' " "The culpable intent is one to cause pain for ' "the purpose of revenge, extortion, persuasion or for any other sadistic purpose." ' " There is no requirement that the victim be aware of the pain. ' ' "However, there must be a causal relationship between the torturous act and death, as Penal Code section 189 defines the crime as murder 'by means of' torture. " ' " (People v. Elliot (2006) 37 Cal.4th 453, 467; see also People v. Proctor (1992) 4 Cal.4th 499, 530.) " 'The finding of murder-by-torture encompasses the totality of the brutal acts and the circumstances which led to the victim's death.' 'For purposes of proving murder by torture, the intent to inflict extreme pain "may be inferred from the circumstances of the crime, the nature of the killing, and the condition of the victim's body." But the Court "cautioned against giving undue weight to the severity of the victim's wounds, as horrible wounds may be as consistent with a killing in the heat of passion, in an 'explosion of violence,' as with the intent to inflict cruel suffering." ' " (People v. Elliot, supra, 37 Cal.4th at p. 467; see also People v. Mungia (2008) 44 Cal.4th 1101, 1137 " The Court, however, cautioned against giving undue weight to the severity of the wounds' " when determining the intent to torture based on the circumstances surrounding the commission of the offense.)