Police are investigating the death of a man who was found unconscious with head wounds on a southbound F train in Brooklyn.

Around 2:30 a.m. on Friday, a 911 call alerted police to an unresponsive man on a Brooklyn-bound F train at the Jay Street subway station at the corner of Willoughby Street, according to authorities.

RELATED: Subway rider dragged to death by F train

Officers found a man, 24, with apparent head trauma between two train cars, police stated. Medical personnel moved the man to Brooklyn Hospital, where he was pronounced dead.

According to media reports, the man appears to have been subway surfing when he injured his head. 

Sources told the New York Post that the alleged surfer was on top of the train as he smashed his head in a tunnel before falling between the two cars.

The medical examiner will determine what killed the man, whose name has not been released, police said.