Transit police are urging the public to report open and gross crimes they see while aboard MBTA trains and at stations following an incident resulting in an arrest at North Station Monday.

Mehmet Beyaztas, 24 of Boston was arrested Monday after a witness told police she saw him masturbating on an inbound Lowell commuter rail train, according to the Transit Police News blog.

Police want to make the public aware of this sort of crime noting in a following blog post that such crimes tend to go under reported.

“[W]e hope it encourages others who have had similar experiences to contact and report the incident to Transit Police,” the blog says. "Our detectives will work tirelessly to identify and hold the offender responsible for their criminal conduct.”

The blog instructs victims of such crimes to bring attention to the person, tell others around you, move away if possible, take a picture if safe to do so and report the incident to Transit Police as soon as practicable. Also, passengers can call 617-222-1212 24 hours a day, 7 days a week or use the MBTA’s SeeSay app, according to the blog.