but in 2005, doug larsson took over the case. he wondered if anything else from the car might yield a more complete dna profile. he sent michelle's blood stained dress back to the state crime lab. >> got the phone call from the lab analysts that they had found a full dna profile on the dress, which was very exciting. >> that's a pretty exciting phone call? >> that's great. all we had to do with submit the profile to codis -- >> codis? it's >> an fbi computerized systems that come teens millions of profiles that have been collected from crime scenes, from jails, people who have been arrested. >> and anything come back? >> nothing. no hit. >> to larsson, that meant michelle's killer was likely someone about any prior arrest or run-ins with a lot. that meant compute people police police had talked back in the day had to be reconsidered. >> my thinking is, let's start going through this case. let's start finding potential suspects. and the school get their dna and start eliminating them from that partial profile. >> so, now are we ba