The trial focused intensely on DNA evidence credibility. Barry Scheck cross-examined LAPD criminalist Collin Yamauchi about evidence handling, glove-changing, and an undetected incorrect genotype in a mock study. Prosecutors responded through Yamauchi and DOJ criminalist Gary Sims with testimony about extraction procedures, contamination exclusions, DNA quantities, and degradation, arguing that cross-contamination was unlikely and that the rear-gate stains were consistent with the prosecution's timeline. The jury viewed sock 13-B through a stereomicroscope, and photographs of reddish staining associated with a stain that tested consistent with Nicole Brown's DNA were introduced. On recross, Scheck elicited that the rear-gate samples contained up to 270 times more DNA than the Bundy drops, that Sims had not verified Yamauchi's notes underlying Harmon's hypotheticals, and that front-gate and handrail samples were degraded unlike the rear-gate samples, points the defense used to challenge the prosecution's account.

• Yamauchi admits crime scene collectors Fung and Mazzola could not be sources of critical allele found on Bronco steering wheel.
• On recross, Yamauchi acknowledged that a mock vaginal-swab study recorded an incorrect DQ-Alpha genotype that neither he nor his supervisor had flagged as an error.
• Jury individually examines sock 13-B through stereomicroscope; all 16 jurors view physical evidence directly.
• Photographs of reddish staining on socks introduced showing blood consistent with Nicole Brown's DNA profile.
• On recross, Scheck elicited that rear-gate samples contained up to 270 times more DNA than the Bundy drops, while Sims did not confirm that the front and rear gates were the same substrate.
• Judge admonishes counsel for speaking objections and personal comments about opposing counsel's competence.
• Phenolphthalein blood test results barred from admission due to lack of written documentation from criminalist Matheson.