he felt that it would be better to just go for a ride or to go out and have his car wired. reporter: so police did just that. then hid a transmitter in the trunk so the detectives could follow and listen in. test, test, test. reporter: 9:30 p.m. matt picked up cyndi at her house. how s it goin ? well, you know. kids are finally passed out. reporter: they went to a bar where matt turned on a phone app to capture the conversation while they weren t in the car. well, i m gonna get a beer. i wanted us to all be comfortable together. i hadn t seen her in years. reporter: he didn t push too hard, didn t probe. this is just my second drink. reporter: for now he was just an old friend, catching up, till, past midnight, then i drove her home and, y know, she didn t get out of my car, which is good, but it got to the point, it seemed like an hour in where she wasn t saying anything. uh, anything relevant.