Did the Court of Appeal err in holding an instructional error on the defense of mistake of fact harmless? In the circumstances of this case, which standard of prejudice applies to an error in instructing on the defense of mistake of fact: that of People v. Watson (1956) 46 Cal.2d 818 or that of Chapman v. California (1967) 386 U.S. 18?

Held:

Early one October morning, defendant Isaiah Hendrix walked up to a house in Oxnard, knocked on the door, and rang the doorbell. Hearing no response, Hendrix walked around the house to the backyard, opened a screen door, and attempted to open the locked glass door behind it. Then, failing that, Hendrix sat down on a bench and stayed there. Hendrix was sitting on the bench when police arrived. Hendrix told police he was there to visit his cousin, but Hendrix’s cousin did not, in fact, live in the house. Hendrix was charged with burglary.

At trial, the court gave the jury a standard mistake of fact instruction, which informed jurors that they should not convict Hendrix if they determined he lacked criminal intent because he mistakenly believed a relevant fact—namely, that the house belonged to his cousin and not to a stranger. But the instruction specified that the mistake in question had to be a reasonable one. All parties now acknowledge this was error: To negate the specific criminal intent required for burglary, a defendant’s mistaken belief need not be reasonable, just genuinely held. The question before us is whether the instructional error was prejudicial and thus requires reversal. The Court of Appeal, concluding Hendrix’s claim of mistake was not credible in any event, answered no. We reach a different conclusion. The instructional error effectively precluded the jury from giving full consideration to a mistake of fact claim that was supported by substantial evidence, where resolution of the issue was central to the question whether Hendrix possessed the criminal intent necessary for conviction. Whether that claim is credible is a matter for a jury to decide. We reverse the judgment of the Court of Appeal and remand for further proceedings.

This case was decided on 8/22/2022.

Review on this issue was also granted with briefing deferred in:

• People v. Franco (Nov. 20, 2020, E069494) [nonpub. opn.], review granted 2/24/2021 (S266338)
• People v. Bradt (Oct. 22, 2021, A158999) [nonpub. opn.], review granted 12/29/2021 (S271949)