Prosecutors have formally charged a man in the death of a woman set alight on a New York subway train.

On Friday, Sebastian Zapeta was indicted on charges of murder and arson, though he did not appear during the brief court hearing.

Mr Zapeta, 33, is accused of setting fire to the woman, who may have been asleep on the train, and fanning the flames with a shirt. The victim has not been identified.

The suspect has been held without bail since his arrest shortly after the incident.

The BBC has contacted Mr Zapeta's lawyer for comment.

Police say the woman was sitting on a stationary train at the Coney Island-Stillwell Avenue Station in Brooklyn on Sunday morning when she was approached by a man who used a lighter to ignite her clothing.

There was no interaction between the pair before the attack and police believe they did not know each other.

Officers extinguished the flame, but the woman died at the scene.

The man got off the train as police officers on patrol in the station rushed to the fire, but he did not flee immediately and his face was captured on police body cameras.

At a news conference earlier this week, New York Police Commissioner Jessica Tisch described the incident as "one of the most depraved crimes one person could possibly commit against another human being".

"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.

The suspect then left the scene, and authorities say three high school students later recognised him in images distributed by police.

Mr Zapeta, who is originally from Guatemala, was deported from the US in 2018 and later re-entered the country illegally, immigration authorities said.

In a preliminary hearing on Tuesday, prosecutor Ari Rottenberg said Mr Zapeta told investigators that he had been drinking and did not remember the incident, but did identify himself in photos and surveillance video showing the fire being lit.

New York City Mayor Eric Adams has urged federal authorities to also charge Mr Zapeta with arson, in addition to the state charges that he currently faces. In a statement, the mayor said: "Lighting another human being on fire and watching them burn alive reflects a level of evil that cannot be tolerated."

A vigil was held Thursday evening for the victim, who was burned so badly that police have had difficulty identifying her.

False and unverified information about her, including a fake AI-generated picture, has been circulating online. Brooklyn District Attorney Eric Gonzalez told reporters on Friday that authorities are still working to identify the woman using fingerprints and DNA.

Mr Zapeta is due back in court on 7 January, prosecutors said.