dr. belenky was on mother's day 2013. >> reporter: turns out dr. was living in the northwest, dividing his time between vancouver and washington state at the time of the brumback murders. when detectives reinterviewed him, they wondered if they were missing something. could their primary person of interest have somehow slipped in and out of omaha undetected? >> reporter: any indication that he was in omaha? >> none. none. >> reporter: for his part, belenky told the cops he had nothing to do with the omaha killings, in fact, he denies ever saying he was glad dr. brumback was dead. in the end detectives had to scratch dr belenky off their list. back to the drawing board. if the suspect wasn't michael belenky, detectives figured it had to be someone else with creighton connections. >> we knew that we had to look at everybody in the pathology department, all of the staff, everybody there. >> reporter: that means there are, what, maybe a thousand, a couple thousand persons of interest all going in different directions? >> yeah. >> reporter: four days af