Hans-Joachim Klein (born 1947) is a former member of the German left-wing militant group Revolutionary Cells (RZ). His nom de guerre was "Angie". In 1975, Klein participated in an attack on OPEC headquarters in Vienna organized by the international terrorist "Carlos the Jackal", in which he was seriously injured. He publicly renounced political violence two years later. After decades in hiding, he was arrested in 1998, prosecuted for his role in the OPEC attack, and sentenced to nine years imprisonment. He was paroled in 2003.
Klein came from a working-class background. His mother was imprisoned in Ravensbrück concentration camp for Rassenschande ("racial pollution") during World War II. She killed herself a few months after Klein was born and he spent some time in a foster home after her death. Klein was physically abused by his father, who took custody of him again after he remarried. For most of his life Klein believed incorrectly that his father had been an SS member and his mother had been Jewish.
In the 1970s Klein worked for the legal Red Army Faction prisoner support group Red Aid (Rote Hilfe) in Frankfurt and subsequently for the RAF lawyer Klaus Croissant in Stuttgart. At one point he shared a Frankfurt commune with Joschka Fischer and Daniel Cohn-Bendit. He served as Jean-Paul Sartre's chauffeur when Sartre visited the imprisoned Andreas Baader in December 1974. He joined the RZ in 1975. Klein has described Holger Meins' death on hunger strike as inspiring his turn to violence; he carried a photo of Meins' emaciated body in his wallet. He took part in the 1975 attack on an OPEC conference in Vienna organized by Carlos the Jackal, in which three people were killed and Klein himself was shot in the stomach.