Authorities are investigating a fatal stabbing on a subway in Brooklyn.

According to police, officers responding to a call about an attack on the southbound N train at Stillwell Boulevard in Coney Island around 11:30 p.m. Tuesday reported that a 54-year-old man was found stabbed in the neck.

The man who was taken to the hospital was declared dead.

Police said they were looking for a bald suspect in his 30s who was wearing a green shirt and swim shorts at the time of the attack. He was last seen running toward Stillwell Avenue.

It is not clear what led to the fatal stabbing, nor is it known whether the victims knew each other beforehand.

Anyone with information is asked to call Crime Stoppers at 1-800-577-TIPS.