CHELSEA (PIX11) – An MTA worker was hit five times in the head with a hammer by an unknown suspect after an argument in a Manhattan subway dispatch room, police said.

The attacker broke into the dispatch room to argue with an assistant train dispatcher on the L train platform at the 14th Street/Eighth Avenue subway station around 2 a.m., according to police. The argument led to a fight, and the assailant hit the dispatcher five times in the head with a hammer, police said. It was unclear what the argument was about, authorities said.

The attacker then ran away and attempted to hide underneath a parked train at the station, police said. Officers found the suspect and arrested him early Tuesday morning, police said.

As of Tuesday morning, investigators had not identified or charged the assailant, who was taken to a hospital for a psychological evaluation.