it was her daughter-in-law diana. detectives knew that diana s friend, karen hamm-samuel, had bought the tracfone that called peggy s house just before she was murdered. diana had told police from the beginning that she d been in washington, d.c., to attend a wedding. but her alibi was wobbly. diana couldn t account for her time in d.c. she hit washington at about 9:30 and didn t reappear again until about 8:00 the next morning. reporter: so detectives called diana, asking her to fill in the gaps. i just have to confirm that you were up in washington. is there somebody i can talk to? what do you mean? we had to keep it real simple with her. listen. we just want to get you cleared. where did you spend the night? reporter: what did they not tell diana? detectives had a warrant and they were tapping her phone. police now sat back and listened as diana made multiple calls to
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.