What is the test for admissibility of evidence of an uncharged crime?

The least degree of similarity is required to establish relevance on the issue of intent. (People v. Ewoldt, supra, 7 Cal.4th 380, 402, 27 Cal.Rptr.2d 646, 867 P.2d 757.) For this purpose, the uncharged crimes need only be "sufficiently similar [to the charged offenses] to support the inference that the defendant " 'probably harbor[ed] the same intent in each instance." [Citations.]' " (Ibid.) Considering the shared characteristics noted above, we conclude also that the trial court did not abuse its discretion when it ruled that the charged and uncharged offenses are sufficiently similar to support an inference that defendant harbored the same intents -- to rape and to kill -- in each instance.

There is an additional requirement for the admissibility of evidence of uncharged crimes: The probative value of the uncharged offense evidence must be substantial and must not be largely outweighed by the probability that its admission would create a serious danger of undue prejudice, of confusing the issues, or of misleading the jury. (People v. Ewoldt, supra, 7 Cal.4th 380, 404-405, 27 Cal.Rptr.2d 646, 867 P.2d 757.) On appeal, a trial court's resolution of these issues is reviewed for abuse of discretion. (Id. at p. 405, 27 Cal.Rptr.2d 646, 867 P.2d 757.) A court abuses its discretion when its ruling "falls outside the bounds of reason." (People v. De Santis (1992) 2 Cal.4th 1198, 1226, 9 Cal.Rptr.2d 628, 831 P.2d 1210.)