With the public’s help, police arrested a person involved in the death of a woman who caught fire on an F train in Brooklyn Sunday morning, officials announced.

Authorities said the man and the victim, both of whom were not identified, were in the same car when it pulled into the Stillwell Avenue station at the south end of the line shortly before 7:30 a.m. and “calmly” walked toward the motionless man They spotted a woman and, according to them, used a lighter to set fire to her clothing, which was completely consumed within seconds.

The fire spread inside the train car at the terminal, according to photos reviewed by Gothamist. Officers patrolling the station saw and smelled the smoke and, with the help of an MTA employee, extinguished the flames with a fire extinguisher.

Police said the woman was pronounced dead at the scene.

NYPD Commissioner Jessica Tisch said three “high school age” students called 911 and reported recognizing the suspect from images police shared with the public earlier in the day. That led to officers spotting the man later Sunday evening during a subway ride in midtown Manhattan, authorities said.

“Transportation officers responded to the 911 call and discovered the man, wearing the same gray hoodie, wool hat, paint-splattered pants and brown boots, already on another moving train,” Tisch said. “The person we were looking for was also found with a lighter in his pocket.”

MTA Chief Security Officer Michael Kemper said the onboard video cameras allowed officers to quickly figure out what happened.

“It provided investigators with immediate answers to their questions,” he said. “It offered them images of the perpetrator and allowed them to take those images and release them to the public and allowed the public to see something and say something and that’s why we’re standing here now reporting that a person is in custody.” ”

Joseph Gulotta, chief of the New York Police Department, said the victim and the subject had not interacted at all before the crime and that police do not believe they knew each other. The incident remains under investigation.

“This is a great job that the public and police have done together,” Gulotta said. “Once again, someone saw something, we figured it out using numerous technologies, and we are able to quickly make an arrest on this nothing less than heinous crime committed on our subway system.”

MTA officials said traffic on the F Line to and from Stillwell Avenue was temporarily suspended following the fire. Services resumed late Sunday afternoon, officials said.