KUALA LUMPUR, Malaysia (AP) — An independent investigation report released more than four years after Malaysia Airlines Flight 370 disappeared is highlighting shortcomings in the government response that exacerbated the mystery.

The report reiterated Malaysia's assertion the plane was deliberately diverted and flown for over seven hours after severing communications. It said the cause of the disappearance still cannot be determined and the "possibility of intervention by a third party cannot be excluded."

It's presumed to have crashed in the far southern Indian Ocean. The report issued Monday followed a second, private search that failed to find the plane.

Family members of those onboard the plane said they were frustrated as there were many gaps in the investigations and questions left unanswered.

The plane with 239 people on board vanished March 8, 2014.