Peter Hanington: "Search teams are looking for any clue"

As the first underwater video of the mangled wreckage was released, Canadian investigators said they were confident they would eventually piece together the sequence of events that brought down Flight 111 off Canada's Atlantic coast two weeks ago.

Chief accident investigator, Vic Gerden, said: "We have a considerable amount of information and we're looking forward to having additional wreckage information to corroborate what we already know."

But he said investigators no longer believe they can rely solely on information from the plane's flight data and cockpit voice recorders, both of which stopped six minutes before the plane crashed.

Scouring the seabed

Operation is difficult and dangerous

Now they believe the answers may lie at the bottom of the sea in sophisticated electrical equipment being sought by divers amid the jagged wreckage.

However, the pieces of debris are so small and distorted that they are difficult to identify.

Watch the underwater footage

"Further wreckage examination will be needed to tell us the source of the problem," Mr Gerden said.

"It's a very, very difficult process - time consuming and potentially hazardous if not done right."

Two of the plane's three engines also have been sighted and may provide additional clues about the apparent power failure aboard the plane.

Identifying the passengers

Among the twisted fuselage, the remains of 142 victims have also been found.

80 relatives have given DNA samples

Using DNA matching techniques, in addition to conventional methods such as dental records, investigators been able to identify 10 individuals.

But chief medical examiner, Dr John Butt, said the work was far from over.

DNA fingerprints have been taken for the remaining 132 victims, but these still have to be matched with DNA samples from the victims' families.

"We need help from family members in order to make a match. Only they can provide us with the information that can make the link," said Mr Butt.