PEOPLE v. WILLIAM
Filed 7/6/06
IN THE SUPREME COURT OF CALIFORNIA
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v. )
Defendant and Appellant. ) Super. Ct. No. FCR182521
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This murder case presents a narrow, but important, question regarding the admissibility of deoxyribonucleic acid (DNA) evidence to prove identity in criminal prosecutions. A DNA comparison of blood found at the crime scene with defendant's blood resulted in a match. That is, defendant's genetic profile matched that of the blood at the crime scene so that he could not be excluded as a donor of that blood. Similarly, a DNA comparison of blood found on defendant's pants when he was arrested with the victim's blood resulted in a match, so that the victim could not be excluded as a donor of that blood. Obviously, evidence tending to show that defendant's blood was found at the crime scene, and that the victim's blood was on defendant's pants, would be highly probative to whether defendant was the killer.
When a match is found, the next question is the statistical significance of the match. Of course, a match is less significant if the blood could have come from many persons rather than from only a few. Experts calculate the odds or percentages--usually stated as one in some number--that a random person from the relevant population would have a similar match. The question here revolves around exactly what is the relevant population. The question is complicated by the fact that the odds vary with different racial and ethnic groups. Because of this variation, separate databases are maintained for different population groups, and the odds for each group are calculated separately. In this case, as in many cases, no evidence exists of the racial or ethnic identity of the perpetrator other than evidence indicating that defendant was the perpetrator. Over defense objection, the trial court permitted the prosecution to present evidence of the odds as to the three most common population groups in this country--Caucasians, African-Americans, and Hispanics. For example, the evidence showed that only one Caucasian in 96 billion would match the crime scene blood that matched defendant's profile.
Defendant contends the court erred. Relying heavily on the opinions in People v. Pizarro (1992) 10 Cal.App.4th 57 (Pizarro I), and especially, People v. Pizarro (2003) 110 Cal.App.4th 530 (Pizarro II), he argues that evidence regarding any particular population group is irrelevant absent independent evidence that the perpetrator was a member of that group. The Court of Appeal concluded that the trial court correctly admitted the evidence. We agree. As Justice Parrilli, author of the majority opinion below, stated, â€
