Malaysian officials and U.S. intelligence have intensified their search for the missing Malaysia Airlines Flight MH370 to include the jet's pilots. after Prime Minister Najib Razak confirmed Saturday that the plane’s communications systems were disabled manually, news reports said.

"I think from all the information I've been briefed on from, you know, high levels within homeland security, national counterterrorism centre, intelligence community, that something was going on with the pilot," said Michael McCaul, House Homeland Security Committee’s chairman, Agence France-Press reported Sunday, citing Fox News. "I think this all leads towards the cockpit, with the pilot himself, and co-pilot," McCaul added.

Malaysian police searched the homes of both pilots, and are examining their flight simulators to get more leads on the fate of the missing plane, The Washington Post reported Monday. 

Local authorities are also investigating a 29-year-old passenger on the missing Boeing 777, Mohamad Khairul Amri Selamat, who is an aviation engineer and reportedly worked with Execujet Aviation Group, a private jet charter company, according to Reuters.

"Yes, we are looking into Mohd Khairul as well as the other passengers and crew. The focus is on anyone else who might have had aviation skills on that plane," a senior police official said Monday, according to Reuters.

Investigations so far have shown that the transponders on the plane, which went missing March 8 with 239 passengers on board, were switched off 14 minutes after the pilots' last communication of, “All right, good night,” according to AFP.