Defense attorney Robert Blasier cross-examined LAPD criminalist supervisor Gregory Matheson about accreditation, written procedures, crime-scene checklists, evidence booking and tracking, the Rockingham socks, Bronco examinations, contamination controls, and evidence collection practices. Matheson made concessions including that the lab lacked accreditation, no formal field operations manual existed, June 13 checklists were incomplete, and no contemporaneous documentation was generated for an identified PCR-lab contamination incident, while disputing or qualifying other defense premises. Judge Ito also ruled on defense demonstrative exhibits, heard argument over whether Robert Kardashian could be compelled to testify about a Louis Vuitton garment bag, and continued a defense prosecutorial-misconduct motion pending review of an FBI agent's declaration.

• Matheson conceded the LAPD crime lab lacked accreditation and had no formal field operations manual since 1992
• Defense exposed that crime scene checklists from June 13th were incomplete with blank sections on scene alterations
• Matheson estimated that two to three months elapsed before the socks were examined carefully; he had no photographs taken before his September 18 cuttings but was unsure whether Yamauchi photographed them earlier
• Matheson said he might have used stricter handling during a defense-observed evidence review, while testifying that laboratory examinations did not photograph every item
• Lab applied same swab to multiple Bronco pedals and stored wet bloodstains in plastic for up to seven hours
• Ito sustained objections to argumentative labels on defense demonstratives, generally allowed the underlying diagrams, and conditionally excluded the blood vial chart pending foundation
• Matheson said no contemporaneous documentation was generated for an identified PCR-lab contamination incident and that he did not know its precise duration
• Blood found on the outside of victim reference vials
• Court heard argument on whether Robert Kardashian could be compelled to testify about a Louis Vuitton garment bag, with the prosecution acknowledging uncertainty about the bag's identity
• Defense alleged misconduct based on Harmon's call to Dr. Rieders and questions about secret EDTA testing; Ito deferred ruling pending review of Agent Martz's declaration