LAPD criminalist Collin Yamauchi testified extensively on DNA typing results from O.J. Simpson's Bronco, with blood samples from the driver's area typed as consistent with Simpson. A center console stain showed a mixture of Simpson and victim alleles, sparking evidentiary battles over whether inconclusive test results could be presented to the jury. The judge sustained some defense objections on foundational issues but ultimately allowed inconclusive findings to be presented. Yamauchi also testified that during Henry Lee's examination of the socks, Lee wore no lab coat or hairnet and Yamauchi did not see him change gloves.

• Judge Ito ruled that PCR/DQ-Alpha results lacking 'C dot' control cannot be presented as definitive type determination
• Yamauchi testified blood from Bronco driver's door interior (item 23) and carpet (item 25) typed consistent with Simpson and inconsistent with both victims
• Center console stain (item 31) showed a mixture of alleles consistent with both Simpson and Goldman
• Judge overruled defense objection and allowed inconclusive item 31 results to be presented to jury despite foundation concerns
• Yamauchi testified that during Dr. Henry Lee's over-an-hour February 1995 examination of the socks, Lee wore no lab coat or hairnet and Yamauchi did not see him change gloves
• Judge sustained defense objection to leading questions about proper sample handling procedures