Three weeks into the investigation regarding the disappearance of the flight and Malaysian authorities say they have no leads and may never know what caused the plane to vanish.
"At the end of the investigations, we may not even know the real cause. We may not even know the reason for this incident," Inspector General of Police Khalid Abu Bakar told reporters in Kuala Lumpur.
Abu Bakar also said that since all 277 passengers have been investigated and cleared of possible involvement in hijacking, sabotage, or having personal or psychological problems, authorities are focusing their efforts on the pilots and crew of the plane.
He said that the police are investigating the cargo and food served on the plane to eliminate the possibility that the people on the plane were poisoned. They are not ruling out the possibility of mechanical failure, but say the evidence suggests that the plane was purposely diverted off course by someone on board.
Malaysian authorities have taken sharp criticism for mishandling the investigation and holding back information from other countries involved in the search and from the families of missing loved ones. The search for the plane, powered by more than 25 nations, has been narrowed down to the southern Indian Ocean, but all debris found in the search area has been found to be unrelated to the plane.
Families of the victims were informed March 24 that the flight was considered lost with no survivors.
Notable deaths of 2014 [PHOTOS]