When Malaysia Airlines MH370 dropped off the radar shortly after it departed Kuala Lumpur on March 8, officials were at a loss.

The search for the missing Boeing 777 shifted dramatically in the days that followed, from the South China Sea to the Andaman Sea and finally to the southern Indian Ocean, where Malaysian Prime Minister Najib Razak says it is now believed the flight "ended."

The search focus has shifted to thousands of kilometres from Australia's west coast, where pings consistent with signals emitted from a plane's black boxes have been reported.

Meanwhile, investigators are probing the backgrounds of the crew and the passengers, part of an intensive effort to determine why or how the plane diverted from its original route.