French authorities are investigating whether a deliberate act of sabotage caused the passenger train derailment that injured 44 people in northern France on Friday evening.

Prosecutor Sébastien Gallois confirmed that the leading line of inquiry is that a piece of rail was lying on the tracks near the commune of Cléon, south of Rouen, potentially causing the train to leave the line. Hervé Morin, the president of the Normandy region, told the AFP news agency that the incident was likely "criminal", pointing out that another train had passed safely over the same stretch an hour earlier and no maintenance work had taken place in the meantime.

A spokeswoman for the French national police communications service, SICOP, said the metal section found on the line was "probably" linked to the crash. Investigators have seized the train's data recorder and appointed an independent court expert to determine whether the obstruction was placed intentionally or got there accidentally, though prosecutors emphasised that inquiries remain at an early stage.

There has also been positive news regarding the most severely injured passenger. Prosecutor Gallois confirmed that while the 18-year-old woman airlifted from the wreckage remains in hospital, her condition has improved and her life is no longer in danger. Transport Minister Philippe Tabarot said 21 of the 26 lightly injured passengers treated across medical centres in Rouen were discharged overnight, with most remaining casualties expected to follow shortly.

The regional TER service was carrying 180 passengers between Rouen and Caen when it derailed at around 19:45 local time. While initial reports from French media suggested that three carriages had overturned, officials have since clarified that one carriage overturned and four others came off the tracks.

Following the incident, emergency services activated a mass-casualty plan, deploying 140 firefighters and police teams to secure the area and triage passengers. State railway operator SNCF continues to report significant disruption across the local network and has put replacement bus services in place for passengers travelling on the Rouen–Caen route.

Local authorities are still advising the public to steer clear of the site while recovery and forensic teams complete their work. I will be following the investigation closely as French prosecutors and rail specialists begin analysing the black box data and interviewing witnesses.