In what circumstances will the trial court exclude evidence that a third party was present at the scene of the shooting?

Similarly, in People v. Samaniego (2009) 172 Cal.App.4th 1148, 1172-1173, the trial court excluded the defendants' proffered evidence that the victim, a drug dealer, got into an argument with, and was threatened with a knife by, a third party on the day he was shot and killed. The eyewitness to the shooting did not identify the third party as having been present, and another witness (familiar with the third party's voice) who heard the assailants could not identify the third party as having been one of them. (Id. at p. 1175.) The appellate court concluded that while the defendants' evidence showed that the third party had motive and opportunity, the evidence was properly excluded because there was no evidence that he was involved in any way with the murder. (Ibid.)

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