assistant d.a. moran didn't think so. peggy would never have let a stranger like andrea benson into her house. so that had to be a friendly voice on the phone? >> yes. >> reporter: detectives thought that voice might have belonged to diana, but they had nothing to put her on the scene, in peggy's house. at this point, is susanne off the hook? >> diana is now the higher suspect. susanne wasn't off the hook. >> reporter: they could be in this together? >> correct. >> yes. that's where it was. >> reporter: because they both benefited. >> absolutely. >> yes. >> reporter: now eight weeks into the investigation detectives still didn't know who had killed peggy nadell. with suspects in florida, d.c., and new york, detectives came up with a new strategy. and their phone expert liked it a lot. >> gutsy. like, i mean, a lot of people don't go to those lengths on a homicide case. i thought it was a brilliant strategy.