The tires on steve s bike. the tread on this tire is similar to the tread we observed of this tire track. and did you find any discernible differences between them? no i did not. reporter: and those shoe prints. they brought in an expert from the fbi. did you find any shoes that seemed to be comparable to the impressions that you observed in these photos from the crime scene? yes. i found one shoe that could have made those impressions. reporter: a la sportiva pike s peak. records showed that steve bought a pair of those shoes two years before the murder. but when detectives searched his house, they didn t find any such shoes. so, intriguing, but hardly proof. prosecutors knew they had a big problem. that anonymous e-mail linking the murder, not to steve, but to jim knapp and illegal drugs. so, even as the trial went on, investigator mike sechez was interviewing and re-interviewing witnesses. including steve s girlfriend,