A New York man has been arrested on suspicion of setting fire to a woman on a Brooklyn subway train.

Police Chief Jessica Tish described Sunday’s incident as “one of the most depraved crimes a person can commit against another person.”

She said the woman was on a stationary F train when a man approached her and lit her clothes on fire with a lighter. “Within seconds, the clothes were completely engulfed.” Although police extinguished the flames, the victim died at the scene.

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

Police said the woman was on a subway car at Coney Island’s Stillwell Avenue station at around 07:30 local time (12:30 GMT) when a man approached her. The woman was not named.

The victim was “motionless” when she was set on fire, but detectives are still determining whether she fell asleep. “We’re not 100 percent sure,” said Joseph Gulotta of the New York Police Department.

Gulotta said there was “no interaction” between the two before the attack, adding that police did not believe the two men knew each other.

Describing how police were informed of the incident, Ms Tish said: “Police patrolling the upper levels of the station smelled and saw smoke and went to investigate.”

“What they saw was a man standing in a train car, engulfed in flames.”

The man got off the train as police patrolling the station rushed towards the fire – although initially he did not appear to go further.

“Unbeknownst to the responding officers, the suspect had remained at the scene and was sitting on a bench on the platform outside the train carriage,” Ms Tisch said.

As a result, police were able to obtain “very clear, detailed” images of the man from the responding officers’ body cameras, she explained. The photos were circulated by the New York Police Department (NYPD).

Ms. Tisch told reporters that three high school New Yorkers later called 911 to report that they recognized the suspect on another subway train.

Police found the man after boarding the train and walking through subway cars.

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

Gulotta added that the man, whose identity has not been made public, immigrated to the United States from Guatemala in 2018.

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