Introduction

People v. Chester Dewayne Turner (10 Cal.5th 786, 2020) is a landmark decision by the Supreme Court of California addressing critical issues surrounding the admissibility of DNA evidence and hearsay in criminal proceedings. The case centers on the conviction of Chester Dewayne Turner, a serial killer responsible for the rape and murder of multiple women over nearly twelve years in Los Angeles's high-crime areas. The appeal primarily challenges two aspects of the trial: the admission of statistical evidence related to DNA matches and hearsay testimony concerning the viability of a fetus involved in one of the murders. This commentary delves into the background, summarizes the court's judgment, analyzes the legal reasoning and precedents cited, explores the impact of the decision, simplifies complex legal concepts, and concludes with the broader significance of the ruling.

Summary of the Judgment

Chester Dewayne Turner was identified as a suspect in multiple unsolved murder cases through DNA evidence that linked him to the victims. Convicted of murdering ten women and one viable fetus, Turner was sentenced to death under California Penal Code § 187(a). The Supreme Court of California affirmed most of the judgment but reversed the conviction related to fetal murder. The primary appellate issues pertained to the trial court's decision to admit statistical evidence demonstrating the significance of DNA matches and hearsay testimony regarding the viability of the fetus.

Analysis

Precedents Cited

The court extensively referenced several key cases to substantiate its rulings:

• PEOPLE v. NELSON (2008): Addressed the admissibility of DNA evidence in "cold hit" scenarios, emphasizing that random match probability remains relevant even when the suspect is identified through a database search.
• PEOPLE v. KELLY (1976): Established the criteria for admitting new scientific techniques in court, requiring general acceptance in the relevant scientific community.
• PEOPLE v. VENEGAS (1998): Discussed the interim ceiling principle in calculating random match probabilities, considering population substructuring.
• People v. Sanchez (2016): Clarified the treatment of hearsay in expert testimony, particularly rejecting the notion that experts can present hearsay as a foundation for their opinions.
• Other cases like People v. Brown, People v. Capers, and Beck and Cruz were cited to uphold the constitutionality of California's death penalty statutes and procedures.

Legal Reasoning

The court's legal reasoning hinged on the distinction between relevance and scientific reliability. Regarding DNA evidence, the court reaffirmed that the product rule—a statistical method calculating the rarity of a DNA profile—is relevant in "cold hit" cases. Despite concerns about ascertainment bias, the court maintained that the product rule's calculation of random match probability sufficiently informs the jury about the improbability of a random match, thereby supporting the defendant's guilt. However, the court recognized that the deposition of fetal viability evidence involved hearsay that did not meet statutory exceptions. This procedural error warranted the reversal of the fetal murder conviction but did not affect the overall judgment.

Impact

The decision in People v. Turner has significant implications for future criminal cases involving DNA evidence and hearsay. It reinforces the admissibility of statistical DNA evidence even in cold hit scenarios, provided that the significance is properly conveyed to the jury. This upholds the utility of DNA databases in solving crimes while maintaining rigorous evidentiary standards. Conversely, the court's stance on hearsay in expert testimony, particularly regarding fetal viability, underscores the necessity for strict adherence to hearsay exceptions, ensuring that only reliable and admissible evidence informs critical aspects of a trial.

Complex Concepts Simplified

Random Match Probability

Random match probability is a statistical measure indicating how likely it is that a random individual from the population would have a DNA profile matching the evidence found at a crime scene. A low probability (e.g., one in a quintillion) suggests that the DNA match is highly significant and unlikely to be coincidental.

Product Rule

The product rule is a method used to calculate the combined probability of multiple independent DNA loci matching between a suspect and DNA evidence. By multiplying the frequencies of the observed alleles across all loci, experts determine the overall rarity of the DNA profile.

Cold Hit Case

A cold hit case occurs when a suspect is identified solely based on a DNA match discovered through an extensive search of a DNA database, without prior evidence or suspicion pointing to them as a suspect.

Hearsay in Expert Testimony

Hearsay refers to statements made outside of court that are presented to prove the truth of the matter asserted. In expert testimony, relying on hearsay without meeting statutory exceptions can render certain evidence inadmissible, as it undermines the reliability of the expert's conclusions.

Conclusion

The Supreme Court of California's decision in People v. Turner serves as a pivotal reference point for the admissibility of DNA evidence and the treatment of hearsay in criminal trials. By affirming the relevance of random match probability in cold hit scenarios, the court validated the continued use of DNA databases in law enforcement investigations. Simultaneously, by reversing the fetal murder conviction due to inadmissible hearsay evidence, the court reinforced the importance of adhering to stringent evidentiary protocols to protect defendants' rights. This judgment balances the pursuit of justice through scientific advancements with the preservation of legal integrity and fairness, setting a clear precedent for future cases in California and beyond.