@ossobuco,
Hah, I looked it up. There was a Petra Schelm in the Baader-Meinhof Red Army faction.
Per wiki,
Petra Schelm joined the Baader-Meinhof group along with her boyfriend Manfred Grashof. She travelled to Jordan alongside the rest of the Gang and trained in urban guerrilla warfare with the PLO in May 1970.
On July 15, 1971, Schelm was driving through Hamburg with Werner Hoppe when she sped her BMW through a police roadblock. The police gave chase and forced her BMW off the road. Schelm and Hoppe ran off in different directions. Hoppe was followed by a police helicopter and was caught and arrested, but Schelm did not surrender. She threw away a jacket she was holding to reveal a handgun and fired at the police, but the police returned fire. Jillian Becker states that Schelm was killed by a burst of gunfire from a submachine gun, but Stefan Aust states that it was a single bullet wound to the head that killed Schelm. Additionally, a closeup photograph of Schelm taken at the scene immediately after her death (probably by a police photographer) clearly shows a single gunshot wound through the eye. Regardless, Schelm died, aged 20.
Some RAF members called for "retribution" for Schelm's death. She was buried at a cemetery in Spandau. At her funeral, fifty or so youths laid a red flag on her grave, though policemen later came and removed it.
Irmgard Moeller bombed the Campbell Barracks in Heidelberg on 24 May 1972. She claimed responsibility in the name of the Commando 15 July (the date of Petra Schelm's death) in honour of Schelm.
Or, and maybe more likely, I was remembering Petra Kelly, one of the founders of the German Green Party.