What is the legal test for corroborating evidence in a murder case?

The requisite corroboration of the testimony of an accomplice "`may be established entirely by circumstantial evidence. [Citations.] Such evidence "may be slight and entitled to little consideration when standing alone. [Citations.]"` [Citation.] `Corroborating evidence "must tend to implicate the defendant and therefore must relate to some act or fact which is an element of the crime but it is not necessary that the corroborative evidence be sufficient in itself to establish every element of the offense charged." [Citation.]' "(People v. Zapien (1993) 4 Cal.4th 929, 982, 17 Cal.Rptr.2d 122, 846 P.2d 704.) Littleton's testimony that defendant shot him and shot and killed his companions was sufficiently corroborated by defendant's own out-of-court admissions and testimony at trial in which defendant admitted shooting and killing the victims. Defendant's admissions and testimony certainly tended to implicate defendant and related to an element of the crime. It was not required that the corroborative evidence establish every element of the crime.

The trial court instructed the jury on reasonable doubt, pursuant to former CALJIC No. 2.90, as follows: "Reasonable doubt is defined as follows: It is not a mere possible doubt; because everything relating to human affairs and depending on moral evidence is open to some possible or imaginary doubt. It is that state of the case which, after the entire comparison and consideration of all the evidence, leaves the minds of the jurors in that condition that they cannot say they feel an abiding conviction, to a moral certainty, of the truth of the charges." Defendant contends this instruction was erroneous, because it uses the terms "moral evidence" and "to a moral certainty" to define reasonable doubt. "`We have repeatedly upheld the efficacy of this instruction, and defendant cites no persuasive reason to revisit this conclusion.' [Citations.]" (People v. Bolin (1998) 18 Cal.4th 297, 330, 75 Cal.Rptr.2d 412, 956 P.2d 374.)

Defendant contends that three jury instructions concerning circumstantial evidence were erroneous because they told the jury that if one interpretation of the evidence "appears to you to be reasonable and the other interpretation to be unreasonable, you must accept the reasonable interpretation and reject the unreasonable." According to defendant, these instructions were contrary to the requirement of proof beyond a reasonable doubt, because they required the jury to accept an interpretation of the evidence that appears, reasonable, which is a lesser standard than proof beyond a reasonable doubt. We have rejected this contention. (People v. Mendoza (2000) 24 Cal.4th 130, 181, 99 Cal.Rptr.2d 485, 6 P.3d 150.)