phone? >> yes. >> reporter: but chandy said she didn't see him may 1st, hadn't heard from him since. last sighting? a colleague saw him driving his black mercedes. >> we felt that 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 -- >> we just waited until she showed up and kind of surprised her. she was very nervous, startled. >> a new witness and the game-changer of a clue. >> i kissed my partner on the cheek. it was pretty exciting. it was a big piece of evidence. >> you think that you can't be shocked, but you can be. >> when "dark valley" continues. ( ♪ )