What is the test for admitting third party evidence in a murder trial?

stricken, there can be little objection to striking the answer that defendant did not know the answer to the question. Beyond that, defendant made no further offer of proof. There was no attempt to present evidence identifying this supposed other person in some manner other than by name. Moreover, the court was correct in requiring a foundation for the admission of third-party culpability evidence. "[T]here must be direct or circumstantial evidence linking the third person to the actual perpetration of the crime." (People v. Hall (1986) 41 Cal.3d 826, 833.) Defendant made no offer to provide such a foundation or to prove any facts tending to identify any other person as the perpetrator of the killing.

Section 354, subdivision (a) states: "A verdict or finding shall not be set aside, nor shall the judgment or decision based thereon be reversed, by reason of the erroneous exclusion of evidence unless the court which passes upon the effect of the error or errors is of the opinion that the error or errors complained of resulted in a miscarriage of justice and it appears of record that: [] (a) [t]he substance, purpose, and relevance of the excluded evidence was made known to the court by the questions asked, an offer of proof, or by any other means." Therefore, "[a]s a condition precedent to challenging the exclusion of proffered testimony, [citation], . . . the proponent [must] make known to the court the 'substance, purpose, and relevance of the excluded evidence.' " (People v. Ramos (1997) 15 Cal.4th 1133, 1178.)