French authorities investigate possible sabotage in Normandy train derailment that injured 44

French authorities are investigating whether sabotage caused a train derailment that injured 44 people in Normandy, after a piece of rail was found on the track.

The regional train was carrying 186 passengers from Rouen to Caen when it derailed Friday evening at Cléon, in the Seine-Maritime department of northwestern France.

An 18-year-old woman was among the injured and was evacuated by helicopter to Rouen University Hospital, police said.

A spokeswoman for the French national police communications service, known as SICOP, said that the piece of rail found on the track was “probably” linked to the derailment. She spoke to the Associated Press on condition of anonymity because she wasn’t authorized to be publicly named in line with police policy.

“At this stage, the leading theory is that a piece of rail was present on one of the tracks, potentially causing the derailment. The reason for its presence is unknown,” said prosecutor Sébastien Gallois in a press release.

"The train's 'black box' has been seized. Several interviews are scheduled, and a court-appointed expert has been called in. The main victim is still in hospital but her life is no longer in danger. The other victims have received care and treatment; they have either been discharged or are about to be."

Investigators were working to establish whether the circumstances were accidental or involved sabotage, the service said. The prosecutor’s office remained cautious about drawing conclusions, according to the police.

France’s previous rail disasters include the July 2013 derailment at Brétigny-sur-Orge, south of Paris, which killed seven people.

In November 2015, a high-speed TGV train carrying out tests derailed at Eckwersheim, near Strasbourg, killing 11.

More recently, a crash involving two high-speed trains at Adamuz in southern Spain killed 46 people and injured more than 100 in January, according to the Andalusian regional government.