An anonymous letter soon surfaced on a left-wing internet platform claiming responsibility for the arson attack. The letter lambasted Rheinmetall for profiting from Russia’s invasion and ended with a curious demand: to free from jail a former member of the Red Army Faction, or RAF, a militant group that murdered prominent German businesspeople and public figures in the 1970s and 1980s, including the CEO of Deutsche Bank in 1989. “His place of retreat is not safe,” the anonymous perpetrators wrote of Papperger.