Prosecutor George Clarke systematically dismantles defense DNA expert Dr. John Gerdes' contamination theory through methodical cross-examination, establishing that multiple independent laboratories obtained OJ Simpson DNA matches despite not involving the allegedly contaminated Yamauchi extraction process. During an in-chambers admissibility argument, prosecutor Harmon said ongoing testing had produced a three-probe RFLP match that he characterized as a mixture consistent with OJ Simpson and Ron Goldman's blood; Scheck disputed that characterization and said the results were unreported, unquantified, and incomplete. Clarke successfully questions Gerdes' methodology, presents alternative explanations for flagged 'contaminants,' and demonstrates that LAPD quality controls effectively detected contamination in validation studies.

• Clarke establishes separate swatches from Bundy and Bronco evidence were independently sent to Cellmark and DOJ — labs that never involved Yamauchi's extraction process — yet all returned results consistent with OJ Simpson DNA
• During admissibility argument, prosecutor Harmon characterized ongoing, unreported three-probe RFLP testing of Bronco console swatches (303-305) as a mixture consistent with OJ Simpson and Ron Goldman's blood; Scheck disputed that characterization and called the results incomplete and unquantified
• Gerdes concedes his 'contamination' notations were often based on faint, difficult-to-see dots and that he reviewed fewer than 100 casework samples
• Clarke tests cross-hybridization and DX gene activity as possible explanations for flagged alleles; Gerdes says some 1-dot activity could not be distinguished as contamination or DX activity and disputes parts of the cross-hybridization premise
• LAPD validation study photograph introduced showing gross contamination successfully detected and flagged by quality controls, contradicting Gerdes' lab critique
• Technical disruption: courtroom projector fails, forcing exhibits to be marked and passed by hand to jury