Hans-Joachim Klein is a German former member of the Red Army Faction, a left-wing militant group active in West Germany during the 1970s and 1980s. He became known for his involvement in various terrorist activities, including the 1975 kidnapping of a German businessman. Klein's actions were part of a broader movement that sought to challenge the political establishment through violence. In the late 1980s, Klein turned himself in to authorities and later cooperated with law enforcement. His decision to renounce violence and provide information about the Red Army Faction marked a significant shift in his life, leading to a more peaceful existence.