The FBI has completed of review of the in-home flight simulator that belonged to the captain of the missing Malaysia Airlines passenger jet and found "nothing suspicious whatsoever."

It was the latest dead end in the investigation of the jetliner's disappearance on March 8 with 239 people on board.

The home-made flight simulator belong to the plane's pilot Capt. Zaharie Shah. It was seized by Malaysian investigators when baffled authorities began to look into the background of the plane's crew. Officials looking for signs that the pilot may have practiced certain routes or maneuvers found that some files had been deleted from the simulator's computer. The simulator was sent to the FBI's lab in Quantico, Va.

"They (FBI analysts) have finished with the simulator. There is nothing suspicious whatsoever about what they found," a senior U.S. official told ABC News.

"There's nothing at all (criminal) about the pilot. Right now there is zero evidence of a criminal act by the flight crew," the official said.

The sources said this creates even more of a need to find the plane and so-called black boxes because the background checks on passengers and crew, at least those done by U.S. officials, have not come up with anything definitive.

Planes and ships from several nations are scouring the southern Indian Ocean looking for signs of the plane.