George Clarke served as the prosecution's DNA specialist, handling the critical Cellmark laboratory evidence and leading the direct examination of Dr. Robin Cotton across multiple days in May 1995. His most decisive contributions came during cross-examination of defense DNA expert Dr. John Gerdes in August 1995, where Clarke systematically challenged the contamination theory by establishing that multiple independent laboratories had obtained DNA matches to Simpson — results that could not be explained by the alleged problems with a single LAPD extraction. Over the course of that cross-examination, Clarke forced Gerdes to concede that multi-probe RFLP matches contradicted his PCR-focused criticisms and that he lacked direct evidence of contamination in key samples.