fbi image analyst richard vorder-brugge scanned the image and examined it digitally on a computer.he immediately saw the problem. the texture of the skin on the victim's leg obscured the fingerprint. >> there were two different patterns we're dealing with here. you are dealing with the pattern of the fingerprint, which is a specific type of pattern, and then we have this texture of the skin that is distinct from the fingerprint. >> with the aid of the computer, vorder brugge first had to identify the victim's skin pattern, then have the computer remove as much of that as possible. >> it's a trial-and-error technique. it's not unlike an archaeologist using a dental tool to scrape away fine pieces and leave the artifact intact, as opposed to taking a pick ax and just swinging for the fences. >> the computer helped identify the repeating patterns of the victim's skin. >> and i can show you how you can get rid of those wavelengths by just sending all of those bright spots to zero. >> and what was left was the print, presumably, of the killer. all investigators needed now was a suspect'