Police are investigating the death of a man found on the exit ramp of the Staten Island Expressway Monday night with a gunshot wound to the head. The man was unconscious and unresponsive when first discovered and later pronounced dead at Richmond University Medical Center, an NYPD spokesperson told Gothamist.

Police discovered the man “in the vicinity of the Staten Island Expressway and Slosson Avenue” after a driver spotted the body and called 911 around 11:44 p.m. According to the NYPD, "EMS responded and transported the male to Richmond University Medical Center where the male was pronounced deceased."

“There are no arrests and the investigation is ongoing,” the spokesperson added. The victim has not yet been identified; according to a CBS New York report, he was a 23-year-old man.

It’s unclear who was responsible for the shooting and how the man wound up on the Staten Island highway. According to the New York Post, police initially thought he had been hit by a car before noticing the gunshot.

There are no identifications or arrests at this time, and police say the investigation is ongoing.