so, investigators tried to find some way to narrow it down. and latent evidence expert ricky navarro looked for clues on kim medlin's clothing. that's when he noticed a print on her sweatshirt. >> at that point in time, i could not determine whether i was looking at a footwear impression or some other type of object that left that impression on the sweatshirt. >> using alternate light sources and high-speed cameras, navarro concluded he was looking at the heel of a shoe. >> it was a type of shoe that was not flat from toe all the way back to the heel. it had a distinct heel in it which, like some of your hard-soled shoes would have, not like your athletic shoes would have. >> and there was a distinct "v," or chevron pattern, across the print. navarro discovered the shoe was