Is a jury allowed to consider the testimony of an informer in a murder trial?

Defendant contends the trial court erred in refusing to instruct the jury pursuant to special instruction A, which would have cautioned the jury to examine with greater care the testimony of an informer. ²⁰ This instruction was patterned upon the federal rule that requires the giving of a cautionary instruction regarding the testimony of an informant when that testimony furnishes the only strong evidence of guilt. (United States v. Patterson (9th Cir.1981) 648 F.2d 625, 630-631.) Defendant contends the giving of this [6 Cal.4th 191] instruction was required because the prosecution's case relied upon the testimony of five witnesses who stated that defendant had confessed to the murders.