PARIS (AP) — The lawyer for an American who was scheduled to testify about his role in the dramatic capture of an Islamic State operative aboard a high-speed train, averting a possible mass slaughter, said Thursday that his witness has been hospitalized, casting doubt on his appearance at the alleged attacker's trial in Paris.

The attorney, Thibault de Montbrial, wouldn't give details about what is ailing Spencer Stone, citing medical privacy. He confirmed that Stone was hospitalized after he flew into the French capital to testify.

Stone, then a 23-year-old U.S. airman, was among passengers who helped subdue gunman Ayoub El Khazzani aboard the Amsterdam to Paris train in 2015.

Their heroics inspired Clint Eastwood to direct a Hollywood re-enactment.