Laura Petrecca

USA TODAY

It's been eight days since a Malaysia Airlines jet seemingly vanished. New reports of the plane flying dramatically off course, as well as an investigation into the role of crew and passengers in the disappearance, have ratcheted up the intrigue surrounded the missing plane.

Beijing-bound Flight 370, with 239 people aboard, lost communication with civilian air controllers about an hour after it took off early Saturday from Kuala Lumpur International Airport. No emergency signals or distress messages were received before the plane dropped from radar.

Here's the latest information on the lost airliner:

The plane's communication systems were disabled

Satellite information shows with a "high degree of certainty," that the plane's Aircraft Communications Addressing and Reporting System, known as ACARS, was disabled just before it reached the East Coast of peninsular Malaysia, according Malaysian Prime Minister Najib Razak. "Shortly afterwards, near the border between Malaysian and Vietnamese air traffic control, the aircraft's transponder was switched off," he said during his latest briefing.

The flight flew for hours after last ground communication

Although the aircraft was flying virtually blind to air traffic controllers about an hour after takeoff, onboard equipment continued to send pings to satellites. The jet's last signal came more than seven hours after it took flight, so the plane could have ended up as far as Kazakhstan or deep in the southern Indian Ocean. Airline officials say the plane had enough fuel to fly for up to about eight hours.

The plane veered dramatically off course

Malaysian air force defense radar picked up traces of the Bejing-bound plane turning back westward, crossing over peninsular Malaysia and then turning northwest, Razak said. "These movements are consistent with deliberate action by someone on the plane," he said. The New York Times reported that American officials and others familiar with the investigation said the flight had significant altitude changes after it lost contact with ground control and varied its course as if still under the command of a pilot.

Crew and passengers fall under scrutiny

Given all the new information, "Malaysian authorities have refocused their investigation into the crew and passengers on board," said Razak. Captain Zaharie Ahmad Shah manned the flight with first officer Fariq Abdul Hamid. Police on Saturday drove into the residential compound where Shah lives in Kuala Lumpur, according a guard and several local reporters who were barred from entering the complex, said the Associated Press. Also on Saturday, a formal "criminal inquiry" into the plane's disappearnce was opened, said The New York Times.

The South China Sea search ends as scouting in other areas begins

Operations in the South China Sea are ending and the search will move to new areas, said Razak. The plane's last communication with the satellite was in one of two possible corridors, according to updates from the prime minister: a northern one from northern Thailand through to the border of Kazakstan and Turkmenistan, and a southern one from Indonesia to the southern Indian Ocean. The massive multinational search effort for the missing plane now involves 14 countries, 43 ships and 58 aircraft.

Malaysian Prime Minster wouldn't confirm a hijacking

Razak acknowledged media reports about a potential hijacking, but stressed that "we are still investigating all possibilities as to what caused MH370 to deviate from its original flight path." A U.S. official told the Associated Press that investigators are examining the possibility of "human intervention" in the plane's disappearance, adding it may have been "an act of piracy." The official, who wasn't authorized to talk to the media and spoke on condition of anonymity, said it also was possible the plane may have landed somewhere.

China critical of communication updates from Malaysia

Flight 370's passengers were of 14 different nationalities, but 152 adults and one infant were Chinese, comprising the majority of the plane's fliers. The Chinese government's Xinhua News Agency criticized the updates coming frm Malaysian leaders, saying they were "painfully belated."Chinese Foreign Ministry spokesman Qin Gang said China has urged Malaysia to increase efforts for search, rescue and investigation, and for Malaysia Airlines to release authoritative information in a timelier manner.

Contributing: Calum MacLeod from Kuala Lumpur, Kim Hjelmgaard from London and Katharine Lackey and Doug Stanglin from McLean, Va., Associated Press