Egyptian investigators say audio from the cockpit voice recorder of the EgyptAir flight that crashed in May shows that pilots attempted to put out a fire onboard.

Speaking on condition of anonymity Tuesday because an official press statement has yet to be released, they say the recordings were consistent with data previously recovered from the plane's wreckage that showed heat, fire, and smoke around a bathroom and the avionics area.

The flight from Paris to Cairo crashed into the Mediterranean, killing all 66 people on board. The pilots made no distress call, and no militant group has claimed to have brought the aircraft down.

Investigators say no theories — including terrorism — are being ruled out, especially since it is rare for a major fire to break out so suddenly.