NEW YORK (CBSNewYork) – The NYPD is investigating what appears to be a murder mystery after a man’s body was found on a highway exit ramp on Staten Island.

Police say he had been shot in the head.

NYPD detectives have been working the scene since a call came in just before midnight from a driver who discovered the body on the Slosson Avenue exit ramp of the Staten Island Expressway.

They say they first thought he was struck by a car but then found a gunshot wound on his head.

“Three gunshots I heard. I know what gunshots sound like,” said neighbor Anthony Lanza. “This morning, I get and I hear that somebody’s dead up there, shot in the head. I can’t imagine.”

Police say it is not clear how the 23-year-old victim got there, reported CBS2’s Jenna DeAngelis.

“Last night I heard the police car racing by, ambulance coming behind it, sirens wailing,” said neighbor Marawan Elrashidy. “Then I saw police quickly move past our backyard and go to the crime scene.”

Police reports say the man was unconscious and unresponsive when first found. He was pronounced dead at Richmond University Hospital.

Investigators also went to a nearby neighborhood, knocking on doors, searching for answers.

“I was awoken about 1 o’clock this morning by a detective who was going up and down to see if anyone heard anything, shots,” said neighbor Jane Foote.

Neighbors also want to learn more after the frightening incident which happened so close to their homes.

“Was he shot in a car and dumped? Was it gang related? We don’t know. Nobody knows anything and we have spoken, I spoke to the neighbors, nobody heard anything,” Foote said. “Very bizarre.”

“We’re all pretty shocked this happened,” Elrashidy said.

Since police say there were no witnesses who saw what happened, they’re checking cameras in the area to try to figure out what led up to the man being left for dead in the middle of the highway.

The NYPD is working to determine if the victim was shot at the location or if he was dumped from a car.