May 29 (UPI) -- The last part of a four-year search for missing Malaysia Airlines Flight 370 formally ended Tuesday as a privately-funded search came to a close.
U.S.-based Ocean Infinity, a company specializing in collecting high-resolution seabed data, said in a statement it would end the hunt after searching more than 43,000 square miles of ocean floor.
The search exceeded the initial target of nearly 10,000 square miles.
"Clearly the outcome so far is extremely disappointing, as a company, we are truly proud of what we have achieved both in terms of the quality of data we've produced and the speed with which we covered such a vast area," Ocean Infinity CEO Oliver Plunkett said. "There simply has not been a subsea search on this scale carried out as efficiently or as effectively ever before."
"We sincerely hope that we will be able to again offer our services in the search for MH370 in future."
Ocean Infinity was given 90 days to find the Boeing 777 on a "no-find, no-fee" basis. A payment of between $20 million and $70 million was promised -- with the fee rising depending on the area searched.
The hunt followed a two-year search by the Australian Transport Safety Bureau with a price tag of $200 million to Australian, Malaysian and Chinese taxpayers. It didn't find the plane, either.
Flight 370 vanished in March 2014 en route from Kuala Lumpur to Beijing. Only pieces of the plane have turned up in the four years since.
"The radar could speak volumes. Was it a failure of the system? Was it a failure of those monitoring the system or was it an intention to ignore or cover up? To me, that is still to be determined," Ibrahim said.
"I am not ruling out further searches in the future depending on what these domestic investigations bring up."
Many relatives of the victims want the searching to continue.
"This is an incident that if unresolved, could happen again," Grace Nathan, whose mother was on MH370, told The Guardian. "They could also ask companies like Boeing or Airbus to contribute. They stand to benefit immensely from safer air travel, are highly profitable and make billions and billions.
"People might think: 'Why are these people still harping on about this, it's been four years'. It's important for people to remember that MH370 is not history."
Several theories as to what happened to the plane have emerged in recent months, including one proposed by international experts this month that the pilot deliberately crashed the plane -- a scenario Australian investigators say is unlikely.