Families of passengers who died on board flight MH370 have been left feeling deflated and hurt after the investigators' "final" report, delivered four years after the plane's disappearance, was inconclusive.
The Malaysia Airlines plane vanished from radar screens carrying 239 people, including six Australians, en route from Kuala Lumpur to Beijing in March 2014.
Dozens of pieces of debris that washed up on Africa's east coast have shown the Boeing 777 went down somewhere in the Indian Ocean, but the main wreckage had not been found when the search was wound up in May.
Chief investigator Kok Soo Chon told reporters in Kuala Lumpur on Monday his team couldn't conclusively determine what happened to the air-worthy and fuelled-up plane.
He said they did not believe the pilot was behind the change in direction to the Indian Ocean, which had to have been done under manual control, and 'unlawful interference by a third party" could not be ruled out.
Grace Nathan, a Malaysian lawyer whose mother Anne Daisy was on board, said many questions still needed to be answered.
These included why none of four transmitters on the plane sent any distress signal and why only two phone calls were made from the ground to the jetliner, five hours apart.
"There is no explanation why there weren't more attempts to contact the aircraft that flew for seven hours," she posted on social media.
"Four years on we are none the wiser."
Victoria-based Jennifer Chong, whose husband Chong Ling Tan was on the flight, said after 1605 days of waiting, the inconclusive report was "unacceptable".
Earlier on Monday, Perth woman Danica Weeks, who lost her husband Paul in the tragedy, said she was angry the Malaysian government didn't offer to fly her from Queensland for a next-of-kin briefing on the report until late last week, which was too little notice.
Malaysia's Transport Minister Anthony Loke had promised to brief relatives of those on board before the report was publicly released.
"A few of us, international families, have been unable to make it in that time frame so I'm very angry about that," Ms Weeks told AAP.
Ms Chong said foreign relatives were not able to watch the briefing via videolink because Malaysia Airlines believed full confidentiality could not be guaranteed.
While relatives were hoping for some closure, Mr Kok said the report couldn't be considered final as no wreckage or victims had been found and there may be another search "but as far as our team is concerned, we have done our job".
Ms Weeks said the search had to go on as the crash may have been due to a problem with the model.
"They need to keep searching - that's a given," she said.
"I understand that without new information, you're throwing the dice and hoping it's there.
"It's a matter of elimination. It's got to be somewhere.
"They can't just push it under the carpet and say 'that's it'."