A man has been arrested in New York in connection with the death of a woman who was set on fire on a subway train in Brooklyn.

Police Commissioner Jessica Tisch described Sunday’s incident as “one of the most depraved crimes one person could possibly commit against another human being”.

She said the woman was on a stationary F train when she was approached by a man who used a lighter to ignite her clothing – which became “fully engulfed in a matter of seconds”. Although officers extinguished the flames, the victim died at the scene.

Police are still working to establish a possible motive for the attack. No charges have yet been filed.

Officers said the woman, who they have not named, was in a subway carriage at the Coney Island-Stillwell Avenue station at about 07:30 local time (12:30 GMT) when a man approached her.

The victim was “motionless” when she was set on fire, but detectives were still establishing whether or not she was asleep. “We’re not 100% sure,” said the NYPD’s Joseph Gulotta.

There was “no interaction” between the pair before the attack, Mr Gulotta said, adding that police did not believe the two people knew each other.

Describing how police were alerted to the incident, Ms Tisch said: “Officers were on patrol on an upper level of that station, smelled and saw smoke and went to investigate.”

“What they saw was a person standing inside the train car fully engulfed in flames.”

The man got off the train as police officers on patrol in the station rushed to the fire – although initially, he appears not to have gone much further.

“Unbeknownst to the officers who responded, the suspect had stayed on the scene and was seated on a bench on the platform just outside the train car,” Ms Tisch said.

She explained that police were therefore able to obtain “very clear, detailed” imagery of the man from the responding officers’ body worn cameras. The pictures were disseminated by the New York Police Department (NYPD).

Later, three high school-aged New Yorkers called 911 to report they had recognised the suspect on another subway train, Ms Tisch told reporters.

The man was located after officers boarded the train and walked through the subway carriages.

He was arrested at Herald Square station – which is located near the Empire State Building in Manhattan. He was found with a lighter in his pocket, Ms Tisch said.

The man, who has not been publicly identified, emigrated from Guatemala to the US in 2018, Mr Gulotta added.

“I want to thank the young people who called 911 to help,” Ms Tisch added. “They saw something, they said something and they did something.”