found near teresa's body. >> that little dirt road still had the tire tracks on it. which was a pretty good catch by the detective. so they did the right thing and preserved the tracks. they did a mold and everything else. and sure enough those tracks had the same tire pattern, tread pattern that the police cars had. but just because someone had a tire tread of the same basic pattern doesn't mean it was that car. >> his former boss, police chief michael brady, was also suspicious of the tire track evidence. soon after lake county investigators left the crime scene he made a discovery that convinced him the evidence was flawed. >> we went out and could find no evidence that the investigators had lifted any kind of tire imprint from the surrounding area. we walked back to the car. that's when smith said, wait a minute, here's something over here. and we found residue from a plaster of paris and i realized the investigators lifted that