KUALA LUMPUR - Malaysia police are looking into possible pilot suicide in their investigation into missing Malaysia Airlines (MAS) flight MH370, as it emerged that the last message from the cockpit - believed to be from co-pilot Fariq Abdul Hamid - came around the time that two of the plane’s crucial signalling systems were manually disabled.

Acting Transport Minister Hishammuddin Hussein confirmed at a daily press briefing on Monday that investigators were looking into the theory of pilot suicide, but declined to say if anyone on board the flight had personal problems.

“Yes, we are looking at it and secondly, no, I cannot say at the moment (what the police have found from investigations),” he said.

Uncertainty also deepened over when the Aircraft Communications Addressing and Reporting System (ACARS) in the missing jetliner could have been switched off. ACARS transmits key information on a plane's condition to the ground.

MAS CEO Ahmad Jauhari Yahya, speaking at the same briefing, said the last ACARS transmission was at 1.07am and the last pilot communication was at 1.19am.

But investigators still do not know if the ACARS was switched off before or after the last pilot communication.

"We don't know when the ACARS system was switched off. What we know is the last transmission," Mr Ahmad said.

"Initial investigations indicate it was the co-pilot who basically spoke," he said. Authorities had earlier revealed that the last message from the cockpit was "All right, good night".

The plane's transponder - which relays radar information on the plane's location - was switched off just two minutes after the voice message.

When asked if the families and relatives of the 239 passengers and crew members on board MH370 should prepare for the worst, Mr Hishammuddin said there's hope as long as there was no distress call or no terrorist demands.

"There is still hope for MH370 since there was no distress call, ransom or any group claiming responsibility," he said.

He added that Malaysia would not withhold any information that would help with investigation, but would not publicly release the information until it has been verified.

The hunt for the missing jetliner entered Day 10 on Monday and has become much more complex, with 26 countries now joining the search in the northern and southern corridors.

The northern corridor goes as far north as Kazakhstan in Central Asia and the southern corridor goes towards the vast Indian Ocean. Australia and Indonesia are coordinating the search in the southern Indian Ocean,

Mr Hishammuddin on Monday refuted claims that Malaysia did not work with foreign agencies, saying it has worked with FBI and Interpol from day one. More Chinese officials have arrived in Malaysia to help with investigation and French officials with experience in dealing with the disappearance of France Flight 447 in 2009 will also assist investigators.

He said Malaysia is requesting radar and satellite information from the countries as well as specific assets for the search. It has sent diplomatic notes to countries involved in the search and rescue operations and has received response for information from half of the 12 to 14 countries it has contacted.

The search entered a dramatic new phase over the weekend after Prime Minister Najib Razak acknowledged on Saturday for the first time that the plane was deliberately diverted.

Mr Najib's revelation refocused attention on the background of the 239 passengers and crew, as well as ground staff.

Police have seized a homemade flight simulator from the pilot Captain Zaharie Ahmad Shah's home and are getting experts to analyse it.