bob dunham: so do i have a missing person that's been battered?ttered somebody else and ran? i mean, there was a lot of questions initially, but no doubt in my mind a serious crime had taken place. did you see any signs of forced entry? no. did that suggest anything to you? pretty well starts the investigation. the victim knows the assailant. or it could be somebody that has a key. andrea canning (voiceover): erika had a roommate, but he had gone to colorado for the weekend. so detectives started talking to the neighbors who told them about some goings on two nights earlier. did anyone hear anything, see anything? there were a few tenants who did hear some banging and noise, you know, i think someone said around 4:00 am in the morning. they just wrote it off as, well, that's just normal sounds that they hear all the time. people are out partying. it's college. andrea canning (voiceover): around that same time, a couple who lived across the street told investigators they heard something more ominous. greg winkler: she did say that her and i believe