The Federal Bureau of Investigation (FBI) of the United States is taking over the investigation of the crash of EgyptAir 990 from the National Transportation Safety Board (NTSB), officials said on November 16.

Investigators doubt that the plane crash, which resulted in the death of all 217 aboard, may have been caused by a criminal act.

Preliminary investigation found that someone in the cockpit uttered a prayer before the jet's autopilot disengaged and the plane started its fatal plunge.

Under the US rules, the NTSB is in charge of the investigation of air transportation accidents while the FBI has jurisdiction over destruction of an aircraft and crimes committed aboard an aircraft.

If investigators conclude the plane was brought down by foul play, they will try to determine whether the perpetrator was assisted by a terrorist group in a suicide plot or acted alone because of a personal problem, the source close to the probe said. The Cairo-bound passenger plane crashed into the Atlantic Ocean off the Massachusettes coast 40 minutes after takeoff from the Kennedy International Airport in New York on October 31.

The cockpit voice recorder was recovered from the ocean floor by a remote-operated robot Saturday after a two-week search.

Speculation about a possible hijacking, crew fight or pilot suicide has lingered because the flight data recorder shows that the plane's autopilot was turned off, the aircraft put into a dive, the throttles cut back and the engines shut off.