KUALA LUMPUR, March 19 — Investigators examining the laptop computers and emails of MH370’s pilots have not discovered anything to explain why the Malaysia Airlines flight was diverted from its flight to Beijing, US investigators said yesterday.

In a report on the CNN news site today, the American officials said they were briefed by Malaysian authorities who took the items from the Shah Alam homes of pilot Zaharie Ahmad Shah and co-pilot Fariq Ab Hamid during searches on Saturday.

The investigators also said that scrutiny of the flight simulator Zaharie built to mimic the Boeing 777-200ER used for the missing plane found no suspicious flight paths that might have been used after the plane disappeared over the Straits of Malacca.

Former inspector-general for the US Department of Transportation Mary Schiavo told CNN, however, that the lack of incriminating evidence in this case was not surprising.

“I've worked on many cases where the pilots were suspect, and it turned out to be a mechanical and horrible problem,” Schiavo, who also served as the news network’s aviation analyst, said.

“And I have a saying myself: Sometimes an erratic flight path is heroism, not terrorism. And I always remind myself of that, not to jump to that conclusion. Sometimes pilots are fighting amazing battles, and we never hear about it.”

A hypothesis that is gaining traction among aviation circles is one proposed by pilot Chris Goodfellow, who suggested that events on MH370 was indicative of a crew battling with sudden electrical fire.

Goodfellow said such a fire would explain why some of the plane’s electronics, such as the Aircraft Communications Addressing and Reporting System (ACARS) and transponders were disabled.

The aviator also said the altered trajectory indicated that the pilots on MH370 was heading for Langkawi International Airport in the Straits of Malacca, possibly to avoid flying over the Titiwangsa Mountains in the event the plane was forced to descend.

But he also suggested that the plane’s disappearance indicated that the pilots could have been overcome by smoke, and that the plane then flew on to its doom.

Yesterday, a Malay-language daily reported local investigators as saying the flight simulator taken from Zaharie’s home had contained the locations of five runways in the Indian Ocean, which is a possible location of the missing plane based on satellite data.

On Saturday, Malaysia announced that MH370 was likely taken off course through “deliberate action” and that it was refocusing its investigation on the crew and passengers onboard.

The plane with 239 onboard departed from its programmed route to Beijing shortly after departing from Kuala Lumpur International Airport and turned west to the Straits of Malacca, after which it has not been seen or heard from again.