Malaysia Airlines say they believe it was the co-pilot of their missing plane who said “All right, good night” to air traffic controllers before contact with the aircraft was lost.

This radio message, now thought to be from first officer Fariq Abdul Hamid, was at about 1.19 a.m., but it’s not clear whether this was before or after the plane’s data communications system was disabled.

Officials say the last transmission from the Aircraft Communications Addressing and Reporting system (ACARS) was at 1.07 a.m., but they don’t know exactly when it was switched off. It was supposed to transmit 30 minutes later, but never did.

Malaysia Airlines is now on code tango, which means heightened security, and they say they are examining every possible security shortcoming.

China’s intelligence service has been asked to go back through the passenger list of flight MH370 and intensify its scrutiny of that list.

Experts from China’s Civil Aviation and civil aviation investigators from France have now joined the investigating team.

Search underway in northern and southern corridors

Twenty-six countries are now involved in scouring huge tracts of land that cross 11 countries and a vast area of deep, remote ocean, far from the area the original search began in the shallower waters of the South China Sea.

The focus now is on two air corridors: a northern one stretching from central Asia to northern Thailand and the other from Indonesia to the southern Indian ocean.

It’s pings sent automatically to a satellite that have led Malaysia to expand the search to this degree.

Malaysia’s acting transport minister, Hishammuddin Hussein, said the search had already begun in both corridors.

“The Royal Malaysian Air Force and the Royal Malaysian Navy have deployed assets to the southern corridor,” he said. “Two Malaysian ships have been deployed: the offshore patrol vessels KD Kelantan and KD Selangor. This deployment also includes a Super Lynx helicopter, which can operate from either ship.”

Australia, the minister said, had already moved a P-3 Orion aircraft to the area of the Cocos and Christmas Islands and would send an additional two P-3 Orions and a C-130 Hercules to assist in the search. A US P-8 Poseidon aircraft would be travelling to Perth today to help with the search.

The minister said that he understood that every day was prolonging the anguish for the families of those on board flight MH370. Malaysia, too, was missing its sons and daughters, he said. There were 15 Malays on the plane.

Mr Hishammuddin again defended Malaysia against accusations that it is releasing information too slowly.

He said Malaysia would not withhold any information that would help find the plane, but had a responsibility not to release unverified information.

It would be irresponsible to deploy assets on the basis of unconfirmed information, he said.

Pilots’ friends speak out

There continues to be a flood of comments from Captain Zaharie’s friends who say they do not believe he could have hijacked the plane. People are also expressing disbelief that the co-pilot could be responsible.

One local journalist has described Zaharie as being passionate about human rights, democracy and good governance. Others talk about his work in community outreach.

Captain Zaharie, aged 53, is an experienced pilot, who has clocked up more than 18,000 flying hours and joined Malaysia Airlines in 1981. He is described as a geek with an absolute passion for flying.

First officer Fariq, aged 27, has flown for more than 2,700 hours and joined Malaysia Airlines in 2007. He has been accused of committing a security breach in 2011, letting two women into the cockpit on a flight from Thailand.

Officials have declined to comment on reports today in the government-controlled New Straits Times stating that the missing plane flew at 5,000 feet or lower to evade commercial radar detection.