BOSTON — Transit police are searching for a suspect after a random and unprovoked assault aboard an MBTA bus in Dorchester, where a passenger was kicked by a stranger before the attacker fled.

The incident occurred around 3 p.m. on December 9 as the bus traveled near Washington Street and Cedrus Avenue, according to investigators. Police say the suspect suddenly lashed out at an adult male passenger without warning or provocation, kicked him, and then bolted off the bus.

The incident was reported shortly afterward, and officers are now reviewing surveillance footage from the bus as part of the investigation. No arrests have been made.

The latest assault adds to growing concerns about rider safety on the MBTA, where commuters have reported an increase in random acts of violence and disorder.

Transit police are asking anyone with information to come forward as the search for the suspect continues.