>> reporter: how many of you were sitting there reading files? >> there were 21 of us assigned to the tank force, and i think at some juncture almost all of the detectives would get assigned files from creighton. >> reporter: in those personnel files were several names that looked promising. those who were nowhere near omaha on mother's day were eliminated, but a couple of weeks after the brumback killings, detective mois says, his boss handed him a three-ring binder from 2001. this one was thicker than the rest. >> and what i took away after reading that file from front to back was that, in my mind, there was enough information contained in that file that it made a very real possibility that there was a motive to want to harm dr. hunter, dr. brumback or dr. bewtra by that individual.