It was not immediately clear whether investigators thought that deleting the files was unusual. They will want to check those files for any signs of unusual flight paths that could help explain where the missing plane went.
A U.S. official, speaking on condition of anonymity because the official was not authorized to discuss the ongoing investigation by name, said the FBI has been provided electronic data to analyze.
U.S. Attorney General Eric Holder said U.S. investigators are prepared to help any way they can.
Malaysia Airlines Flight 370 with 239 people aboard disappeared March 8 on a night flight from Kuala Lumpur to Beijing. Malaysian authorities have not ruled out any possible explanations, but have said the evidence so far suggests the flight was deliberately turned back across Malaysia to the Strait of Malacca, with its communications systems disabled. They are unsure what happened next and why.
Investigators have identified two giant arcs of territory spanning the possible positions of the plane about 7½ hours after takeoff, based on its last faint signal to a satellite — an hourly "handshake" signal that continues even when communications are switched off. The arcs stretch up as far as Kazakhstan in central Asia and down deep into the southern Indian Ocean.
Police are considering the possibility of hijacking, sabotage, terrorism or issues related to the mental health of the pilots or anyone else on board, and have asked for background checks from abroad on all foreign passengers.
Hishammuddin said such checks have been received for all the foreigners except those from Ukraine and Russia — which account for three passengers. "So far, no information of significance on any passengers has been found," he said.
The 53-year-old pilot joined Malaysia Airlines in 1981 and had more than 18,000 hours of flight experience. People who knew Zaharie from his involvement in opposition political circles in Malaysia and other areas of his life have described him as sociable, humble, caring and dedicated to his job.
The crisis has exposed the lack of a failsafe way of tracking modern passenger planes on which data transmission systems and transponders — which make them visible to civilian radar — have been severed. At enormous cost, 26 countries are helping Malaysia look for the plane.
Relatives of passengers on the missing airliner — two-thirds of them from China — have grown increasingly frustrated over the lack of progress in the search. Planes sweeping vast expanses of the Indian Ocean and satellites peering on Central Asia have turned up no new clues.
"It's really too much. I don't know why it is taking so long for so many people to find the plane. It's 12 days," Subaramaniam Gurusamy, 60, said in an interview from his home on the outskirts of Kuala Lumpur. His 34-year-old son, Pushpanathan Subramaniam, was on the flight heading to Beijing for a work trip.
"He's the one son I have," Subaramaniam said.
Before Wednesday's news briefing at a hotel near the Kuala Lumpur airport, two Chinese relatives of passengers held up a banner saying "Truth" in Chinese and started shouting before security personnel escorted them out.
"I want you to help me to find my son!" one of the two women said.
Hishamuddin said a delegation of Malaysian government officials, diplomats, air force and civil aviation officials will head to Beijing — where many of the passengers' relatives are gathered — to give briefings to the next of kin on the status of the search.