karen kolbe: yeah.h mankiewicz: im wondering whether you felt more of a threat after the second and third murder scenes are-- are sort of announced. natalie collins: honestly, i was scared. but i also knew, or believed, that this was personal. and i felt in my heart of hearts that, when this shooter crossed steve off his list, that he was moving down a list. josh mankiewicz: 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 karens office and discovered they were .40 caliber. same as at the other two crime scenes. four murders now in less than thirty-one hours, all possibly committed by the same person. there was one promising clue. dna on a shell casing recovered at the scene of steve pitts murder. investigators ran it through their system, but there was no match. by 10 am saturday morning, police opened an emergency center. and tips were pouring in. bianca buono: there was a lot of fear. the