The invention is concerned with a closing device, connected to a central-locking system with multi-point operation, for a tailboard door of estate cars. According to the invention, the closing device is designed so that, to prevent thefts of lights on the tailboard door, there is provided a separate securing position of the lock which cannot be selected from the central-locking system and which is to be brought about by a change in the operation of the key on the lock cylinder, and that the particular prevailing security state of the tailboard door can be recognized clearly from the interior.