tampering done? >> the door that was adjacent to where the camera was located, that door also had been propped open that night. >> how do you know that? >> the gentleman working as the clerk that night found a rock that had been placed in the door to keep the door from closing. >> well, then they plugged the camera back in, so it's now working again. and at about 6:35 that morning suddenly that camera is pointing straight at the ceiling. >> same camera? >> same camera. and it's tampered with yet again. >> reporter: if that was jason young's work, is it possible he did make the 340-mile round trip? could he have killed his wife and cleaned up his daughter all in 7 1/2 hours without ever being seen? to find out, investigators played a hunch. they visited every gas station along the route. showed jason's photo, talked to the night clerks. and came across a woman named gracie doms in a tiny place called king, north carolina.