roughly 250 miles from where the plane turned around, picked up a roaming signal from hamid's cell phone, suggesting his was the only phone turned on after the flight's transponder turned off. one u.s. official told cnn, "he could have tried to do something with the phone. we don't know." >> you know, the interesting thing about that is that no other phones connected to it. it was specifically his cell phone. >> reporter: while u.s. and malaysian officials caution there's no evidence the first officer tried to make a call with the phone, on sunday, malaysia's transport minister did not deny the possibility. >> as far as i know, no. but that would be in the realm of the police, and the other international agencies. when the time comes, that will be revealed. but i do not want to speculate on that at the moment. >> reporter: when the plane first went missinging, authorities said millions of cell phone records were searched, looking for evidence calls had been made from the plane, but turned up nothing. still, if hamid's cell phone