DNA analyst Gary Sims from the California Department of Justice testified extensively about RFLP and PCR testing, presenting statistics showing odds of 1 in 21 billion for Nicole Brown Simpson's blood on a sock found in OJ's bedroom. Under intense cross-examination by Barry Scheck, Sims made critical concessions about proper laboratory contamination protocols—sample separation, material handling, cleaning procedures—while Scheck methodically suggested LAPD violated these standards by processing 21 Bronco samples simultaneously and failing to follow documentation protocols. The defense developed its core contamination theory: LAPD technicians processed known suspect samples alongside unknown crime scene samples, creating a cross-contamination risk that could explain the DNA results without proving guilt.

• DNA analyst Gary Sims testified to 1 in 21 billion match odds for Nicole's blood on sock found in OJ's bedroom
• Sims presented PCR frequency statistics ranging from 1 in 50,000 to 1 in 6 million for blood evidence from multiple locations
• Barry Scheck methodically cross-examined Sims and extracted admissions about best laboratory contamination practices
• Scheck revealed LAPD processed 21 Bronco samples at once, exceeding the Amplitype guide's recommended batch size of 15
• Defense exposed documentation failures: LAPD bindles bore pencil initials instead of required ink, lacked proper technician signatures
• Judge overruled Scheck's discovery objection regarding FBI population study but sustained objection to DNA projection hypotheticals
• Newspaper article slipped past jury screening but was immediately reported by diligent juror and deemed harmless
• Two media attendees banned from courtroom after jurors complained about constant disruption