Abstract: Nowdays, it is common seen that criminals tend to use the lock-against-theft for motorcycle to harm others as a tool. In order to find out the chief characters of this kind of injury, 28 cases in which victims were hurt by lock-against-theft for motorcyclewere analyzed. In each case, the victims carefully questioned to confirm the damage procedure. Furthermore, the wound configuration was observed and the forming mechanism was deduced to provide morphological evidences for the judgement in this kind of case.

Key words: wound configuration, lock-against-theft for motorcycle, judgement of tools in a criminal case