Five Teito Rapid Transit Authority employees who were in charge of maintenance at the time of a deadly train crash last March were accused of professional negligence on Tuesday as police handed the case over to prosecutors.

It is the first criminal action taken by investigators into the accident, in which five Hibiya subway line passengers were killed when the last carriage of an eight-car train derailed and sideswiped a commuter train running in the opposite direction on a parallel track near Nakameguro Station.

Tokyo police determined that the five maintenance officials, who were not identified, failed to properly maintain the tracks and, as a result, created one of the factors that led to the collision.