psychotherapist karen kolbe's husband answer the door. >> he came back in to get me and said, you neede are here, marshall has been found dead in the office. >> the latest victim, 72 year old marshall levine, was a counselor and life coach. he was subletting his office from karen. >> we sat down with the officers and they wanted to know what kind of clients was he seen. and what was his practice like. >> the assumption was, this was about marshall? >> i'm wondering when you felt more of a threat after the second and third murder scenes were announced. >> honestly, i was scared. but i also knew, or believed, that this was personal. and i fell in my heart of hearts that when this crossed steve off his list, that he was moving down a list. >> if the killer did have a list, police were racing to find out why were these people on it? what did they have in common? investigators collected shell casings at clearance office and discovered they were 40 caliber. same as at the other two crime scenes. four murders now in less than 31 hours. all possibly committed by the same person. there was one