Police are looking for three people they say are responsible for beating and robbing a man aboard a 2 train in Flatbush.

The NYPD says a woman and two men approached the 33-year-old man around 11:30 p.m. on Oct. 25 while the train was near the Nostrand Avenue and Newkirk Avenue subway station.

The trio punched and kicked the man in the head and body before forcibly taking his bookbag. Police say one of the men displayed a knife.

The man suffered swelling and bruising and was taken to NYC Health and Hospitals/Kings County in stable condition.

Police say the bookbag cost around $46.

The assailants, all approximately 17 to 20 years old, exited the train at the Flatbush Avenue subway station.

Police ask anyone with information to call the NYPD’s Crime Stoppers Hotline at 1-800-577-TIPS.