. >> one pair caught michaud's attention, a pair of size 6 1/2 tennis shoes.the shoes with powder and applied a sticky sheet of acetate to lift the print. all shoe impressions are distinctive. >> when a shoe is made, and it comes out of the factory, it's exactly like every other shoe made in that particular mold. and as soon as you start walking on that shoe, you get microscopic scratches and cuts and nicks in the bottom of the shoe that makes that shoe different from all others in the world. >> the shoe impression found on the glass at the crime scene had various nicks and scrape marks. interestingly, sharon zachary's left tennis shoe was the same size, make and model as the impression found at the crime scene. and it also had the same nicks and scrape marks. >> the surface was so clean, it made just a beautiful, very detailed impression. >> there was enough excellent markings on the glass that she was able to compare to the shoes and find a positive match to one shoe and only one shoe that made that print. >> fingerprint analysts had a more difficult time co