>> andrea benson >> how do you know it's andrea benson >> it's her car registered t her. >> are you goingat dumps from cell phone towers i washington d.c.. >> that allowed them to matc the travel of the cell phones. >> can you follow diana's cell phone? >> it bounced all around washington d.c. simultaneously with andrea's, they were together day-to-day. >> by late friday, the night peggy was murdered, dana's phone stopped moving and wen quiet. but andrea's phone >> we saw andrea's phone hea headed out of the washington area and head up i-95. >> exactly the way you would drive you are heading fo peggy's house. >> exactly >> along the way, the trac foam was activated, and it won 17 a emmitt painted a cell tower right near peggy's house what was going on? was this murder for hire did andrea benson drive up t new york, call peggy on th track phone, somehow get int her house and then murder? this is nda moran didn't think so peggy would never have let a stranger like andrea benso into her house >> that had to be a friendly voice on the phone >> yes >> detectives thought that voice might have b