From Wikipedia, the free encyclopedia. Kenneth Mars (April 4, 1935 – February 12, 2011) was an American television, movie, and voice actor. He may be best-remembered for his roles in several Mel Brooks films: the insane Nazi playwright Franz Liebkind in 1968's The Producers, and the relentless Police Inspector Hans Wilhelm Fredrich Kemp in 1974's Young Frankenstein. Description above from the Wikipedia article Kenneth Mars, licensed under CC-BY-SA, full list of contributors on Wikipedia.