Authorities still have no idea where the missing Malaysia Airlines plane is, but they've found a new place to refocus their efforts—the pilot who said, "All right, good night," a few minutes after the plane was diverted.

The phrase was the last thing recorded after the flight's signaling system stopped transmitting and the plane diverted from its flight path. It's not clear which pilot was speaking.

The plane made a sharp, deliberate turn just after it last communicated with Kuala Lumpur air traffic controllers, and before it would have to communicate with Vietnamese controllers, according to the U.S. official with knowledge of the latest intelligence thinking.

"This is the perfect place to start to disappear," the official said.

Malaysia's defense minister revealed the final message today, refocusing scrutiny on the flight's two pilots, 53-year-old Capt. Zaharie Ahmad Shah and his 27-year-old first officer Fariq Abdul Hamid.

Police have searched both the pilot's homes, albeit a week after the flight's disappearance. Officials are also investigating the flight's 239 passengers, looking for anyone with flying experience.

The authorities may also be looking at an aviation engineer who was among the passengers. The New Straits Times, a newspaper published in Malaysia, interviewed a man who said that his son, an aircraft engineer, had been on the flight en route to China to work on Malaysia Airlines planes.

Officials from 25 countries are now participating in the search, which has yielded scant clues since the plane went missing last Saturday.

UPDATE 9:58 am: According to Malaysian Airlines CEO Ahmad Jauhari Yahya, Fariq Abdul Hamid, the plane's co-pilot, said the last words heard from Flight 370, not the pilot, Capt. Zaharie Ahmad Shah.

[image via AP]