Police are searching for the man who punched an off-duty New York Police Department officer Saturday night while he was waiting on a city subway platform.

NYPD Officer Adrian Delfaus hit his head on the platform after falling, according to 1010 WINS, causing bleeding on his brain. Paramedics rushed Delfaus to Bellevue Hospital, where doctors placed the 29-year-old man in a medically induced coma.

The attacker and Delfaus were arguing around 6:30 p.m. while waiting for the southbound 6 train in the Flatiron District near Gramercy Park when the man punched the officer and fled. The suspect remains at large.

A police spokesman described the man as 5-foot-9, 200 pounds and in his 40s. The attacker was last seen in a white T-shirt and blue jeans. He was with two females, reportedly teenagers, who left with him.

Police are investigating. Whether the man knew the victim is a police officer remains unclear. Delfaus has been with the department for six years.

The New York Post reported that the detective and his cousin were standing on the platform when the cousin began "bothering" a panhandler when the suspect interrupted by punching the detective in the head.

"That's not f*cking right," the suspect yelled before striking the officer. Delano Parsons, the panhandler, told the Post that Delfaus and his companion were the verbally abusive group.

No arrests have been made, and police said there is no surveillance footage of the incident. More than a dozen police officers were scouring the 23rd Street station for other evidence. The station remained closed in both directions Sunday morning because of the investigation.