BEIJING, March 14 -- Western media reports began to suggest Thursday the disappearance of Malaysia Airlines Flight 370 could be a "deliberate act" rather than a catastrophic failure as the possible whereabouts of the missing jetliner still remained a mystery.

U.S. official sources speaking with the ABC News said they believe the data reporting system was shut down at 1:07 a.m. Saturday Malaysia time, while the transponder -- sending out location and altitude data -- was shut down at 1:21 a.m.

In other words, the shutdown of two separate communications systems from the missing flight happened at different times, which indicates the disappearance was more likely caused by a "deliberate act" rather than a catastrophic failure, the report said.

U.S. investigators are "convinced that there was manual intervention," one of the sources told ABC, indicating an accident is not the reason.

"This is beginning to come together to say that ... this had to have been some sort of deliberate act," ABC aviation analyst John Nance told CNN.

If the disappearance of the plane were a result of a catastrophic failure, such as an explosion or engine malfunction, the systems likely would have stopped transmitting at the same time or within a much shorter period. But a 14-minute delay raises even more questions.

The Wall Street Journal also reported that investigators suspect the missing flight stayed in the air for about four hours after it reached its last known location.

And that is why the search-and-rescue efforts for the missing aircraft should expand to the Indian Ocean.

"It's my understanding that based on some new information that's not necessarily conclusive, but new information, an additional search area may be opened in the Indian Ocean and we are consulting with international partners about the appropriate assets to deploy," White House Spokesman Jay Carney was quoted by the newspaper as saying.

One person close to the investigation told The Wall Street Journal that the plane could have been diverted "with the intention of using it later for another purpose."

The WSJ reported earlier that data from the plane's Rolls-Royce engine had raised questions among some U.S. officials about whether the plane had been steered off course, citing a "person familiar with the matter."

The newspaper later corrected its story, saying that data leading investigators to believe the plane had flown for up to five hours came from the plane's satellite-communication link, which it said is "designed to automatically transmit the status of certain onboard systems to the ground."

But Malaysian Acting Transportation Minister Hishammuddin Hussein rejected the WSJ report Thursday, reiterating that the plane sent its last transmissions at 1:07 a.m. Saturday.

Malaysia Airlines Chief Executive Ahmad Jauhari Yahya said Rolls-Royce and Boeing have reported that they did not receive transmissions of any kind after 1:07 a.m. Saturday.

Air traffic controllers lost contact with the plane shortly afterward at around 1:30 a.m.

Erin Atan, a spokeswoman for Rolls-Royce in Asia, declined to comment on the matter, telling CNN it was "an official air accident investigation."

Contacted by Xinhua, a Boeing spokesman said he has no response to the WSJ report, citing the Malaysian authorities are leading the investigation.

Quoting U.S. sources, British newspaper The Daily Mail said the plane was in fact still in contact with satellites operated by Boeing after it lost contact with ground control on March 8.

The airline manufacturer offers a service that can receive a stream of data during flight on how the aircraft is functioning.

Malaysia Airlines did not subscribe to that service, but the plane still had the capability of connecting with the satellite and was automatically sending "pings."

The continuing pings led searchers to believe the plane could have flown more than 1,600 km beyond its last confirmed sighting on radar, it said. The plane had enough fuel to fly about four more hours, it added.

In a related development, Malaysian police said Thursday they were investigating the two pilots of the missing jetliner, although the acting transport minister denied media reports that their homes had been raided.

Malaysia Airlines has said it was "shocked" over allegations raised in an Australian television report that First Officer Fariq Abdul Hamid, 27, along with a fellow pilot, violated airline rules in 2011 by allowing two young South African women into their cockpit during a flight.