What is the proper burden of proof in a murder trial?

[citations].' [Citation.]" (People v. Rogers, supra, 57 Cal.4th at p. 336.)³ The last sentence of defendant's modified instruction cautioned the jury, "Remember, you may not convict the defendant of any crime unless you are convinced that each fact essential to that conclusion that the defendant is guilty of that crime has been proved beyond a reasonable doubt." The trial judge instructed the jury on the proper burden of proof on two other occasions and thoroughly instructed the jury on the elements of first degree murder (including premeditation and deliberation, lying in wait, and felony murder), second degree murder, voluntary manslaughter, and robbery.