chandy.was years in the fast, but phone records show he called her, may 1st, a day before he disappeared. cops tracked her down, too. what did she tell you? >> she acknowledged the prior affair and said she had not been in contact for some time and they had been talking via e-mail. >> reporter: that would explain the fact that he called her on the phone? >> yes. >> reporter: she says she hasn't heard from him since. last sighting a colleague saw him driving his black mercedes. >> we felt the vehicle was still out there somewhere. >> reporter: so find the car and maybe find out what happened to gavin. and nine months after gavin vanished, they finally got the break they were looking for. >> i said, i'm here to talk to you about your daughter and he started crying and he said, she saw everything. >> coming up. >> she was very nervous and startled. >> a new witness and a game changer of a clue. >> i kissed my partner on the cheek, it was pretty exciting. it was a big piece of evidence. >> huge m