Can a declarant who has admitted to murder claim that he acted alone?

The trial court may have been incorrect in its categorical statement that a declarant who has admitted to murder does not enhance his personal culpability by claiming that he acted alone. It is plausible that under some circumstances, as defendant contends, such statements may subject the declarant to a risk of increased criminal liability by establishing aggravating circumstances of the crime under section 190.3, factor (a), which would make the declarant more deserving of the death penalty. (See People v. Carpenter (1997) 15 Cal.4th 312, 414415, 63 Cal.Rptr.2d 1, 935 P.2d 708 [that defendant acted alone could be considered by jury as a circumstance of the crime in determining penalty]; People v. Howard (1992) 1 Cal.4th 1132, 1195, 5 Cal.Rptr.2d 268, 824 P.2d 1315 [defendant's role as the actual killer and motivating force behind the crime was a factor aggravating his culpability].)

[182 Cal.Rptr.3d 76]