The other potentially explosive piece of evidence actually was a fingerprint. "When [the murderer] leaves, there is a gate and there is a brass turnstile on that gate," he says. "There is a thumbprint right on the brass turnstile, in blood. As he went through, he pushed it open."
Mark says his partner found this bloody thumbprint, and he wrote it up very clearly in his notes. "So all these piece of evidence I'm noting, and then when I relinquish it, nobody read my notes for two months," he says. Like the gum, the bloody thumbprint was never used in the criminal trial. In the later civil trial, Mark says, the Brown family used testimony from the locksmith who threw away blood-smeared gate lock to help win a $33.5 million judgment against O.J.