Rockne Harmon served as the prosecution's DNA specialist, an Alameda County Deputy District Attorney brought in to handle what would become a central battleground in the trial: the biological evidence. He conducted the direct examinations of key forensic witnesses including DOJ analyst Gary Sims and LAPD criminalist Collin Yamauchi, methodically walking the jury through PCR testing procedures, evidence handling protocols, and the genetic links between Simpson and the crime scenes. Harmon also mounted an aggressive cross-examination of defense statistics expert Dr. Terence Speed, challenging his qualifications and pressing the point that the prosecution's population frequency estimates stood as the only statistical evidence before the jury. Across dozens of proceedings spanning motions on DNA admissibility, EDTA testing, and RFLP analysis, he was the prosecution's point person for the forensic science evidence.