Police said Thursday they discovered the dead body of a man that had travelled undetected for 900 kilometres (560 miles) across northern India locked inside a train toilet.

They believe the man boarded the train days before it set off from Bihar state and died inside the lavatory after locking the door.

Railway police officer Ram Sahay told AFP they forced the door open on Sunday after passengers complained of the smell.

The Saharsa–Amritsar Jan Sewa Express had by then travelled for nearly 24 hours from its starting point. The entire journey takes 35 hours.

Indian media said the train was delayed for almost five hours while officers tried to check the dead man’s identity with other travellers before the journey to Amritsar was resumed. 

“We still don’t know anything about the man,” said Sahay, who is posted in Shahjahanpur in Uttar Pradesh state where the grisly discovery was made.

“He likely entered the train when it was still parked in the yard and died on his own two or three days before the body was discovered,” he said.

Sanjay Rai, a doctor at the railway hospital, told The Times of India that the man “died after he slipped into a possible coma”. 

The authorities have since distributed missing posters of the man around railway stations in Bihar.

Tens of thousands of dead bodies go unclaimed and unidentified in India each year. They are generally cremated by the police after three days, following efforts to identify any friends or relatives of the deceased.