Military radar-tracking evidence suggests a Malaysia Airlines Flight MH 370, missing for nearly a week, was deliberately flown across the Malay peninsula towards India's Andaman Islands, sources familiar with the investigation on Friday.
Two sources said an unidentified aircraft that investigators believe was Malaysia Airlines MH370 flight was following a route between navigational waypoints - indicating it was being flown by someone with aviation training - when it was last plotted on military radar off the country's northwest coast.
The last plot on the military radar's tracking suggested the plane was flying toward India's Andaman Islands, a chain of isles between the Andaman Sea and the Bay of Bengal, they said.
Waypoints are geographic locations, worked out by calculating longitude and latitude, that help pilots navigate along established air corridors.
A third source familiar with the investigation said inquiries were focusing increasingly on the theory that someone who knew how to fly a plane deliberately diverted the flight, with 239 people on board, hundreds of miles off its intended course from Kuala Lumpur to Beijing.
"What we can say is we are looking at sabotage, with hijack still on the cards," said that source, a senior Malaysian police official.
All three sources declined to be identified because they were not authorised to speak to the media and due to the sensitivity of the investigation.
Officials at Malaysia's Ministry of Transport, the official point of contact for information on the investigation, did not return calls seeking comment.
Malaysian police have previously said they were investigating whether any passengers or crew had personal or psychological problems that might shed light on the mystery, along with the possibility of a hijacking, sabotage or mechanical failure.
The comments by the three sources are the first clear indication that foul play is the main focus of official suspicions in the Malaysia Airlines Boeing 777's disappearance.
As a result of the new evidence, the sources said, multinational search efforts were being stepped up in the Andaman Sea and also the Indian Ocean.
In one of the most baffling mysteries in modern aviation, no trace of the plane nor any sign of wreckage has been found despite a search by the navies and military aircraft of more than a dozen countries.
The last sighting of the aircraft on civilian radar screens came shortly before 1:30 a.m. Malaysian time last Saturday (1730 GMT Friday), less than an hour after it took off from Kuala Lumpur, as the plane flew