People v. Mountain, 66 N.Y.2d 197 (1985)
Evidence of a defendant’s blood type, and that of the assailant, is admissible even if the blood type is common, overruling prior precedent that deemed such evidence lacking in probative value.
Summary
The defendant, a former police officer, was convicted of rape and sodomy. A key piece of evidence was the blood type of the assailant’s sperm. The prosecution sought to link this to the defendant’s blood type, but the defendant objected to the introduction of his own blood type. The New York Court of Appeals addressed the admissibility of evidence regarding common blood types, ultimately overruling its prior holding that such evidence lacked probative value. The court held that such evidence is admissible unless the defendant can demonstrate that the potential prejudice outweighs the probative value.
Facts
A woman was arrested and detained at a police station. The defendant, a police officer, interacted with her, offering assistance with bail. Later, he sexually assaulted her in her cell. The woman collected the assailant’s sperm. Hospital examination revealed sperm in her vagina, and a laboratory examination of the collected sample confirmed the presence of type A blood in the sperm. The defendant was subsequently identified, and handwriting analysis linked him to a note given to the complainant. He was employed part-time as a security guard at the St. Clare’s Hospital.
Procedural History
The defendant was indicted for rape, sodomy, and official misconduct. The trial court allowed evidence that the assailant’s sperm contained type A blood, but sustained an objection to evidence of the defendant’s blood type. The jury found the defendant guilty. The Appellate Division affirmed the conviction. The New York Court of Appeals granted leave to appeal.
Issue(s)
Whether the trial court erred in permitting the prosecution to introduce evidence that the assailant’s sperm contained type A blood, without also admitting evidence of the defendant’s blood type, and whether the prior precedent prohibiting such evidence should be overruled.
Holding
No, because the prior rule excluding evidence of common blood types is not well-founded and should no longer be followed; such evidence is admissible unless the defendant demonstrates that the potential prejudice outweighs the probative value.
Court’s Reasoning
The Court of Appeals acknowledged its prior ruling in People v. Robinson, which held that evidence of a common blood type shared by the defendant and the assailant was inadmissible due to its lack of probative value. However, the court reassessed this rule, finding it to be based on a flawed premise. The court reasoned that while blood grouping alone may not definitively identify the perpetrator, it still possesses probative value. The court noted that sharing a common characteristic, even one shared by a large segment of the population, is still relevant when identity is in issue. Evidence of such characteristics can acquire greater probative value when considered cumulatively with other evidence. The court explicitly overruled People v. Robinson. The court stated: “When identity is in issue, proof that the defendant and the perpetrator share similar physical characteristics is not rendered inadmissible simply because those characteristics are also shared by large segments of the population.” The court further reasoned that concerns about juries according undue weight to scientific evidence can be addressed through appropriate jury instructions. The Court also addressed evidentiary rulings concerning the victim’s credibility and a holster, finding no reversible error in these rulings.