Robert Shapiro served as a lead defense attorney for O.J. Simpson, appearing across both the preliminary hearing and criminal trial over more than a hundred court days. He conducted pivotal cross-examinations of key prosecution witnesses, most notably a methodical challenging of lead Detective Philip Vannatter's credibility by exposing failures in investigation protocols, chain-of-custody procedures, and the accuracy of his search warrant affidavit. Shapiro also aggressively challenged the prosecution's forensic case, cross-examining Chief Medical Examiner Dr. Lakshmanan to unravel time-of-death certainty and questioning the autopsy evidence to expose procedural failures in evidence collection. His examinations spanned a wide range of witnesses — from limousine driver Allan Park and houseguest Kato Kaelin to criminalist Michele Kestler and members of Nicole Brown Simpson's family — reflecting a broad role in shaping the defense's strategy throughout the case.