 Before playing Klein in "Derrick" he portrayed the same character on the popular television drama "Der Kommissar" (1969–1976) from the series' start until 1974 when he was transferred to Derrick.Harry Klein was replaced by his brother Erwin (played by Fritz Wepper's real-life brother Elmar Wepper).Fritz and Elmar Wepper appeared together in the television series "Zwei Brüder" (1994-2000), playing a pair of different brothers hunting criminals and solve difficult cases.