The search of the Indian Ocean off Western Australia has turned up nothing. Pic: AP.

CANBERRA, Australia (AP) — An Australian agency says investigators have concluded that the missing Malaysian jet is not within an area thought to be its most likely resting place after an unmanned submersible found no sign of the plane.

The Joint Agency Coordination Center said Thursday the U.S. Navy’s Bluefin 21 had finished its final underwater mission in the southern Indian Ocean on Wednesday after scouring 850 square kilometers (330 square miles).

The agency said that an expanded search of 56,000 square kilometers (21,600 sq. miles), based on satellite analysis of the plane’s most likely route, would probably begin in August after commercial side-scan sonar operators are contracted.

The plane carrying 239 people vanished March 8 on a flight from Kuala Lumpur to Beijing.