it appeared to be a fragment of a disposable glove. of course they tested it to be sure it did not come from the medical examiner or any of the officers at the crime scene. and it did not. must have been left by the otherwise careful killer. but who would want to hurt her? and so horribly? the first person detective ellzey talked to was shelley's roommate, ashley olvera, who'd found shelley dead in her own bed. that's how ashley became possible suspect number one. >> she wasn't sexually assaulted, shelley. that was my initial opinion. it was later confirmed. >> reporter: yeah. >> why couldn't a woman do this? >> reporter: sure. >> it's her roommate. there's a lot of things happen between roommates that we don't know about. so it very well could have been. >> reporter: sure. what happened, if anything, between these roommates was something detective ellzey was determined to find out. even if he had to get rough. coming up --