Day 81 centered on LAPD DNA analyst Collin Yamauchi's extensive direct examination, in which Harmon walked through PCR testing procedures, evidence handling, and results. Yamauchi said news reports that Simpson was in Chicago led him to expect an exclusion before testing, prompting disputes over examiner-bias questioning and whether the testimony opened the door to Simpson's full statement. The court also addressed defense objections to DNA demonstratives, expert-report discovery, and no-C-dot typing strips. Yamauchi testified that glove stains 9A and 9B produced no results because leather inhibited amplification, stains 9C and 9D yielded mixtures that could not exclude Simpson, Nicole Brown, or Ronald Goldman, and Bundy samples 48, 50, and 52 matched Brown's profile.

• LAPD analyst Yamauchi admits expecting Simpson to be excluded before testing, based on news reports of alibi in Chicago
• Defense challenges accuracy of prosecution's PCR lab board, claiming it shows cleaned-up rather than actual lab configuration
• Dispute erupts over Dr. Gerdes expert report discovery—defense provided only six pages of notes two days before Yamauchi testified
• Judge Ito orders coverage of 'Same gloves' notation on socks examination board after Scheck challenges its accuracy
• Yamauchi's PCR results: glove stains 9A/9B produced no results because leather inhibited amplification; 9C/9D yielded a mixture that could not exclude Simpson, Nicole Brown, or Ronald Goldman; Bundy samples 48, 50, and 52 matched Nicole Brown's profile
• Defense objects to testimony about Yamauchi's awareness of media reports, and Judge Ito limits examiner-bias questioning
• Defense objects to prosecution's use of DQ-Alpha typing strips without C dot, citing lack of scientific foundation for interpretation