Autopsies of the Air France disaster victims revealed leg, hip and arm fractures – which experts say suggest the plane broke up in the air.

With more than 400 bits of debris recovered from the ocean’s surface, the top French investigator expressed optimism about discovering what brought down Flight 447, the Associated Press reported.

“Typically, if you see intact bodies and multiple fractures, it’s a good indicator of a midflight breakup,” said Frank Ciacco, a former forensic expert at the National Transportation Safety Board.

The pattern of fractures was reported by Brazil’s O Estado de Sao Paulo. It said some victims were found with little clothing, and had no burns.

That lack of clothing could be significant, said Jack Casey, an aviation safety consultant in Washington.

“In an in-air breakup like we are supposing here, the clothes are just torn away,” he said.

An Airbus A330 jet with 228 passengers on board crashed on May 31. The number of recovered bodies from the crash has reached 41. Vessels sweeping the Atlantic Ocean search for another 187 that have yet to be found.