KUALA LUMPUR - The co-pilot of the missing Malaysia Airlines flight MH370 was the one who said "All right. Good night", initial investigations showed, Malaysian officials said.

Malaysia Airlines CEO Ahmad Jauhari Yahya revealed this at a daily press conference on Monday.

It was also revealed that the Aircraft Communications Addressing and Reporting System (ACARS) had been deliberately shut down just after Kota Baru, and the transponder turned off near Igari.

Mr Jauhari told reporters that the last transmission from ACARS was at 1.07am on March 8 but it was unknown when it was switched off. It did not transmit 30 minutes later as programmed.

The hunt for the missing Malaysia Airlines jetliner entered a dramatic new phase over the weekend after Prime Minister Najib Razak acknowledged 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.

Mr Hishammuddin revealed on Sunday that an internal communication system was turned off before someone in the cockpit said "All right, good night" to Malaysian air traffic control. This took place about 40 minutes after the plane took off.

It was also revealed that the pilot Captain Zaharie Ahmad Shah, 53, and co-pilot Fariq Abdul Hamid, 27 did not ask to fly together on this flight.

Police have seized a homemade flight simulator from Mr Zaharie's home and are getting experts to analyse it.

It has also emerged that co-pilot Mr Fariq has plans to marry a fellow pilot from another airline.