KUALA LUMPUR, Malaysia — Investigators are trying to restore files deleted last month from the home flight simulator of the pilot aboard the missing Malaysian plane to see if they shed any light on the disappearance, Malaysia’s defense minister said Wednesday.

Hishammuddin Hussein told a news conference that the pilot, Capt. Zaharie Ahmad Shah, is considered innocent until proven guilty of any wrongdoing, and that members of his family are cooperating in the investigation. Files containing records of simulations carried out on the program were deleted Feb. 3, Malaysian police chief Khalid Abu said.

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.

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,” Hishammuddin said.

The 53-year-old pilot joined Malaysia Airlines in 1981 and had more than 18,000 hours of flight experience.