Lethal Obsession(1987)

Original title: Der Joker

Several known criminals already have been murdered by a professional killer, leaving no trace but the "ace" game card. The police suspects a new mob is trying to take over the district. The investigating police officer Jan is victimized by a bomb himself, when he's at his girlfriend Daniela's father's Italian restaurant. Although paralyzed and suspended from work, the tuff cop continues to investigate and takes revenge on the gangsters who did this to him.