Police are asking for the public’s help in identifying a person who they say brandished a gun and threatened an 18-year-old man on a northbound 2 train this month.

Authorities say it happened near White Plains Road and Pelham Parkway.

The suspect sat next to the victim, began arguing with him and then pulled out the gun.

No shots were fired, and no injuries were reported.

Detectives urge anyone with additional information to call 1-800-577-TIPS.