DNA expert Gary Sims endured intense cross-examination by defense attorney Barry Scheck focused on challenging the integrity of DNA evidence from the crime scene and Bronco. The central battleground was the stark contrast in bacterial degradation between blood samples collected from the rear gate on June 13th (showing degradation) and July 3th (showing none), which the defense suggested implied potential evidence planting. The prosecution repeatedly redirected to rehabilitate Sims' testimony through technical explanations of contamination safeguards and proper evidence handling procedures.

• Barry Scheck conducted multiple cycles of recross-examination attacking DNA evidence collection integrity and procedures
• Defense highlighted stark bacterial degradation differences between June 13 and July 3 rear gate samples as potential evidence of planting
• Prosecution repeatedly rehabilitated Sims' testimony with technical defenses of contamination protocols and storage conditions
• Sidebar dispute erupted over hearsay regarding Greg Matheson's prior knowledge of LAPD serology testing on the sock
• Defense introduced handwritten examination notes documenting glove cutting G1-G4 collection procedures