Crew members look outside windows from a Malaysian air force CN235 aircraft during a search-and-rescue operation to find the missing Malaysia Airlines Flight 370 over the Strait of Malacca. Prime Minister Najib Razak said on Saturday that Malaysia was ending its search for the vanished jetliner in the South China Sea after investigations indicated the missing plane likely turned far to the west.

March 15, 2014 Crew members look outside windows from a Malaysian air force CN235 aircraft during a search-and-rescue operation to find the missing Malaysia Airlines Flight 370 over the Strait of Malacca. Prime Minister Najib Razak said on Saturday that Malaysia was ending its search for the vanished jetliner in the South China Sea after investigations indicated the missing plane likely turned far to the west. Mohd Rasfan/AFP/Getty Images

In the most comprehensive account to date of the missing Malaysia Airlines Flight 370’s fate, Malaysian Prime Minister Najib Razak on Saturday said that the plane was steered off course after its communications systems were intentionally disabled and that it could have flown for seven additional hours.

In the most comprehensive account to date of the missing Malaysia Airlines Flight 370’s fate, Malaysian Prime Minister Najib Razak on Saturday said that the plane was steered off course after its communications systems were intentionally disabled and that it could have flown for seven additional hours.

In the most comprehensive account to date of the missing Malaysia Airlines Flight 370’s fate, Malaysian Prime Minister Najib Razak on Saturday said that the plane was steered off course after its communications systems were intentionally disabled and that it could have flown for seven additional hours.

Malaysia called for satellite and radar data from 22 countries as the search for a missing airliner evolved to include a massive criminal investigation alongside the physical hunt for the plane.

U.S. officials confirmed that they had examined the names of the passengers and crew members on ­Malaysia Airlines Flight MH370 for possible connections to terrorist groups — none have been disclosed — but also expressed frustration that Malaysia had not asked for more extensive help from the FBI in investigating what is now thought to be a “deliberate act.”

India said Sunday that it had suspended its involvement in the search for the plane until it becomes clearer where its ships and planes should be looking — or how its officials might support the criminal side of the probe. Privately, Indian officials were also upset over Malaysia’s handling of the case and the massive area they were expected to scour — an example of how regional tensions and backbiting have plagued the investigation.

Attention focused Sunday on the plane’s pilot and co-pilot after authorities searched the homes of both men and removed the captain’s flight simulator.

Analysts tried to divine the significance of the fact that a satellite-based flight data system on the plane had been shut down before a crew member — or whoever was in the cockpit — signed off to Malaysian air traffic control with a seemingly innocuous “All right, good night” before the plane left Malaysian airspace.

View Graphic Malaysia has asked more than 20 countries for help in locating Flight MH370.

That detail, confirmed by Malaysian authorities, suggests that the person at the controls of the plane continued to indicate that all was fine even though the Aircraft Communications Addressing and Reporting System, known as ACARS, had gone off-line. The plane’s transponder — a separate device that provides a precise location to radar systems — was shut down later. The sequence of events, analysts say, appeared consistent with an effort to conceal the aircraft’s position and direction as it veered from its intended northeast path toward Beijing.

Ron Carr, who spent 39 years flying for the Air Force and American Airlines before becoming a professor at Embry-Riddle Aeronautical University in Arizona, said that it is “very rare” for ACARS units to malfunction but that the system could be deliberately switched off through its circuit breaker.

From a regional search a week ago in shallow waters in the vicinity of a presumed crash, the disappearance of Flight MH370 has now forced authorities to think along two equally complex tracks: how to find a plane that may have wrecked anywhere over tens of thousands of square miles of ocean and land, and how to home in on a theory about who steered it astray and why.

The physical search now spans much of Asia and extends deep into the Indian Ocean, toward areas where debris could remain unnoticed for years. At the same time, no evidence has surfaced indicating a perpetrator or motive for a criminal act. Even if passengers initially survived whatever happened, the plane carried only limited emergency supplies.

House Intelligence Committee Chairman Mike Rogers (R-Mich.) said on CBS’s “Face the Nation” on Sunday that none of the theories about the fate of the plane had risen “from plausible to the probable.” Despite the speculation about flight directions and timelines, the aircraft may well be “at the bottom of the Indian Ocean,” he said.

Still, Malaysian officials are trying to collect radar and other data from nearly two dozen countries in hopes of picking up the airplane’s vanished trail. They said Sunday that they were examining the flight simulator from the home of Zaharie Ahmad Shah, 53, the plane’s captain. Investigators also interviewed his family, removed other items from his house and searched the nearby home of the co-pilot, Fariq Abdul Hamid, 27.

Malaysian Defense Minister Hishammuddin Hussein cautioned against jumping to conclusions. Zaharie and Fariq had not requested to be on the flight together. They also did not request extra fuel.

International investigators arrived in Malaysia to help in the hunt for the jet missing for more than a week with 239 passengers and crew on board. (Reuters)

‘It just doesn’t add up’

Malaysia’s investigation was given a new degree of focus over the weekend after experts determined that the plane had been deliberately flown off-course, its various communications systems severed. After dropping off civilian radar, the plane tacked to the west, then remained in the air for as many as seven additional hours. Experts have suggested that the plane could have been guided only by a skilled aviator — willingly or under duress.

Khalid Abu Bakar, inspector general of Malaysia’s police, said Sunday that investigators had not found any passengers who had aviation expertise, although some governments with passengers aboard had yet to submit detailed profile information. Abu Bakar added that “a few foreign intelligence agencies” working with the Malaysians had “cleared all the passengers” — meaning that they had determined that no citizen of theirs could have operated the plane.

Zaharie had flown for the airline for more than 30 years and showed no recent signs of trouble, said Peter Chong, a friend who says he saw the plane’s captain the week before the flight’s disappearance.

Zaharie had planned to attend a community event this week to chaperon needy children on a mall shopping trip, Chong said.

The pilot’s flight simulator is a three-panel console that he built and proudly showed off on social media networks. Friends have described him to local news organizations as a tech geek who spent his free time fiddling with devices. On his YouTube page, he demonstrated handy do-it-yourself home maintenance tips. He also was a social activist, a skilled cook, a husband and the father of three adult children.

“If you look at him, suicide — it just doesn’t add up,” said Chong, an aide to a Malaysian parliament member, who has known Zaharie for two years. “As far as I know, he had no financial problems. It just doesn’t add up. There are so many unanswered questions.”

Khalid said Sunday that investigators were looking at airport workers on the ground who might have serviced the plane before it departed on its red-eye flight bound for Beijing. Although investigators have not detailed what they are looking for, experts familiar with airplane accidents say they are likely to look for recent changes in personality, financial problems, signs of depression or any unusual contacts.

“The first thing I’d be looking for is to see whether the captain flew a flight profile like the one we’ve been talking about for the last eight days,” said Greg Feith, a former National Transportation Safety Board investigator involved in the 1996 ValuJet Flight 592 crash and the 1997 SilkAir Flight 185 disaster — a suspected case of pilot suicide. “Did he normally simulate flights to places he wouldn’t normally go?”

In the case of SilkAir, the pilot placed the Boeing 737 into a high-speed dive, according to the NTSB. The plane broke the sound barrier on the way down, then disintegrated into an Indonesian river. Before the incident, the pilot, Tsu Way Ming, had reportedly suffered heavy stock losses and arranged an insurance policy to protect his family in the event of his death.

Even if search teams do find the missing Malaysia Airlines plane, they may never be able to figure out what happened in the cockpit as the jet veered off-course. A cockpit voice recorder, which would have recorded any activity or commotion, captures only two hours of sound, constantly overwriting the oldest material. Because the plane flew on for many more hours, the key events have been wiped away. If searchers do find the “black box,” they’ll instead have to rely on a flight-data recorder, which provides technical information about the plane’s behavior.

First week’s faulty search

Based on an analysis of satellite contact the plane made in its final hours, investigators think it could have ended up anywhere along one of two massive arcs, extending north into Asia and south into the Indian Ocean. The northern and southern corridors are being treated with “equal importance,” Hishammuddin said.

The northern corridor crosses 11 countries from Thailand to Kazakhstan. The southern is far more remote and stretches through areas that are uncovered by radar. To help with the northern area, Malaysia’s government has requested help from nearly a dozen Asian countries — including Burma, Pakistan, Bangladesh, Uzbekistan and Turkmenistan — and Australia. The Malaysian Foreign Ministry on Sunday held a briefing for 22 countries and asked them to share satellite and radar data that may give clues to the plane’s whereabouts.

Malaysia has already burned the resources of more than a dozen countries by focusing the first week of the search on nearby waters — areas that now appear far from the flight’s endpoint. With the latest information from satellite data, the search has expanded to include 25 countries, up from 14.

“This is a significant recalibration of the search,” Hishammuddin said.

Halsey reported from Washington, and Gowen reported from New Delhi. Liu Liu in Beijing and Howard Schneider and Sari Horwitz in Washington contributed to this report.