The trial focused intensely on DNA evidence credibility, with Barry Scheck conducting searching cross-examination of LAPD criminalist Collin Yamauchi on evidence handling procedures and a critical error in a mock DNA study where he reported an incorrect genotype without his supervisor catching it. Prosecutors responded with testimony from DOJ criminalist Gary Sims about DNA analysis of the contested socks evidence, which the jury was allowed to examine directly under a stereomicroscope. Scheck's subsequent recross revealed a dramatic disparity in DNA quantities between the rear gate samples (collected three weeks later) and the earlier Bundy drops, suggesting potential contamination or evidence inconsistency. The day highlighted deep divisions between prosecution and defense over the reliability of DNA evidence handling and whether blood traces were genuinely deposited on the timeline prosecutors claimed.

• Yamauchi admits crime scene collectors Fung and Mazzola could not be sources of critical allele found on Bronco steering wheel.
• Defense reveals mock DNA study where Yamauchi reported incorrect DQ-Alpha genotype that neither he nor his supervisor detected—raising systemic credibility issues.
• 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.
• Scheck demonstrates rear gate samples contained up to 270 times more DNA than Bundy drops despite supposedly similar outdoor exposure and earlier collection date.
• 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.