Dr. Robin Cotton, laboratory director of Cellmark Diagnostics, testified as a DNA expert over six trial days in May 1995, explaining PCR and RFLP testing, laboratory procedures, and chain-of-custody protocols and presenting analysis of blood evidence from Ron Goldman's boot, the Bundy walkway, the Rockingham foyer, and a sock, including reported rarity figures for the sock evidence ranging from one in 6.8 billion to one in 530 billion. On cross-examination, Peter Neufeld challenged Cellmark's procedures, controls, evidence handling, and proficiency testing; the testimony addressed missing substrate-control swatches and reagent blanks, while the defense advanced degradation and contamination hypotheses concerning evidence stored in hot, unrefrigerated conditions. Cotton also testified in the civil trial with Renee Montgomery and Gary Sims about DNA evidence from Bundy, Rockingham, the Bronco, the glove, and the socks, stating that the sock blood was well preserved and almost certainly did not come from Nicole Brown's degraded autopsy reference sample.