An Apple device might be at fault for the EgyptAir Flight 804 crash that took place in 2016, with French officials now investigating whether an iPhone or an iPad caused a fire due to overheating.

French newspaper Le Parisien reports that French investigators believe an Apple device might have been plugged in while flying, eventually suffering from overheating and leading to an explosion on board. The investigation involves an analysis of an iPhone 6s and an iPad Mini 4, which were brought in the pilot cabin by the flight’s first officer.

An expert from the French National Center for Scientific Research, together with a duo of engineers working as part of France’s Ministry of Defense, have already started the investigation to determine whether the Apple devices were indeed the ones that brought the aircraft down or not.

The EgyptAir Airbus A320 was flying from Paris to Cairo on May 19, 2016, when it crashed in the Mediterranean Sea, with a total of 66 passengers and crew losing their lives. Fifteen French citizens were on board.

Expert to analyze iPhone battery

One of the three experts is specialized in battery tech, which means that authorities are looking into the typical battery overheating that’s causing phones to burst into flames when charging. Several iPhones caught fire earlier this year and in 2016, but Apple has never confirmed overheating to be the cause.

Apple, on the other hand, says it’s not involved in the investigation, and added in a statement for BI that it wasn’t contacted by French authorities until now.

“We haven't been contacted by [Air Transport Gendarmerie] or any authority investigating this tragic event. We have not seen any report, but we understand there is no evidence to link this event to Apple products. If investigators have questions for us, we would, of course, assist in any way we can. We rigorously test our products to ensure they meet or exceed international safety standards,” a company spokesperson was quoted as saying.

On the other hand, the possibility of an iPhone to have caused the crash does not align with an investigation started by Egypt, as authorities in the country believe that a real explosion brought the airplane down. Egyptian officials said in late 2016 that explosive residue was discovered inside the aircraft, but no terrorist group claimed the attacks and no other evidence to support this theory was discovered ever since.