New York: New York City police announced on Monday (AEDT) they have in custody a “person of interest” in the early morning death of a woman who they believe may have fallen asleep on a stationary subway train before being intentionally lit on fire by a man she didn’t know.

Transit police apprehended the suspect after receiving a report from three high school students who had recognised the man. They had seen images of the suspect taken from surveillance and police body cam video and widely distributed by police.

“New Yorkers came through again,” said New York City Police Commissioner Jessica Tisch, who described the case as “one of the most depraved crimes one person could possibly commit against another human being”.

Tisch said the suspect and the woman, both of whom have not been identified, were riding a subway train without any interaction between them to the end of the line in Brooklyn at around 7.30am.

After the train came to a stop, surveillance video from the subway car showed the man “calmly” walk up to the victim, who was seated motionless, possibly sleeping, and set her clothing on fire with what appeared to be a lighter. The woman’s clothing then “became fully engulfed in a matter of seconds,” Tisch said.

Police do not believe the two knew one another.

Officers on a routine patrol at the Coney Island-Stillwell Avenue subway station smelled and saw smoke and discovered the woman on fire, standing in the middle of the subway car. After the fire was extinguished, emergency medical personnel declared the woman dead at the scene.

Unbeknownst to the officers, the suspect had remained at the scene and was seated on a bench on the subway platform, just outside the train car, Tisch said. Body cameras worn by the officers caught a “very clear, detailed look” at the suspect and those images were publicly disseminated.