A mentally deranged man has been arrested by the New York Police Department (NYPD) for setting ablaze a homeless woman.

The incident occurred on Sunday when the suspect approached the victim on a train car and set her on fire before fleeing the scene. 

According to the NYPD, the suspect and victim were riding on a train to the end of the line at Stillwell Avenue in Brooklyn. 

Confirming the incident, Jessica Tisch, the NYPD commissioner, explained that the suspect used a lighter to ignite the victim’s clothing, “which became fully engulfed in a matter of seconds.”

Ms Tisch revealed that the police were conducting a routine patrol at the station when they encountered the victim on fire inside a subway car. 

“The officers smelled and saw smoke” that prompted them to investigate, leading them to the subway car where they discovered the victim was on fire. 

“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, and the body-worn cameras on the responding officers produced a very clear detailed look at the killer,” she said. 

Ms Tisch added that the suspect appeared calm when initially approached the victim.

She further noted that there was no interaction between the victim and the suspect during the attack, stressing that the police did not believe that the suspect and the victim knew one another.

The person who set the victim on fire appeared to retreat from the train car, sit on a bench at the station, and watch as the victim stood and burned, according to the police. 

The police, however, added that body cameras and surveillance images were key to apprehending the suspect