Evidence Code section 1108 allows a trier of fact to consider prior sexual offenses as propensity evidence only when the defendant is accused of a “sexual offense,” that is one in which sexual misconduct is an element of the charged offense or applicable enhancement, not where it is just a circumstance of the crimes commission. During appellants murder trial for killing a prostitute, the prosecution was allowed to introduce evidence of three prior sexual assaults (two committed against prostitutes) to prove identity, motive, and intent pursuant to Evidence Code section 1101, subdivision (b), and predisposition pursuant to Evidence Code section 1108, subdivision (a). Appellant alleged the prior crimes were inadmissible under either section. The Court of Appeal found the evidence admissible under section 1101, but not under section 1108. Section 1108 allows admission of prior sex offenses where the crime charged is either an enumerated felony, or one having an element of deriving sexual pleasure or gratification from the infliction of death, bodily injury, or physical pain. Neither was the case here. However, the error was harmless because direct physical evidence linked appellant to the victim and supported the conclusion he had sex with her shortly before her death.