Verena Becker, a former Red Army Faction member arrested last week in connection with a political murder committed three decades ago, for years worked as a secret service informant.
German media reports said she was paid as much as $70,000 for tips that led to the arrest of several other RAF terrorists.
Last week Becker was arrested in her apartment in Berlin because police found new evidence linking her to the 1977 murder of Siegfried Buback -- then Germany's top terrorist hunter.
Buback in April 1977 was driven to work when two masked individuals on a motorbike approached the car and emptied their machine guns into it, killing Buback and two bodyguards. The killing marked the beginning of the German autumn, a period of bombings, abductions and assassinations staged by the RAF, the far-left terrorist group that terrorized Germany for more than two decades.
A court convicted the four RAF terrorists -- Christian Klar, Knut Folkerts, Guenter Sonnenberg and Brigitte Mohnhaupt -- of planning and executing the Buback murder, but the prosecutor's son Michael Buback and several experts have long questioned the validity of that verdict.
Becker in 1977 was sentenced to life in prison for seriously wounding a police officer (she was pardoned in 1989). She should have been a serious suspect for the Buback murder as well: When Becker and Sonnenberg were arrested, they were in possession of the weapon that killed Buback -- but Becker was never tried for that.
Instead, she tipped off German authorities on the whereabouts of Klar and Mohnhaupt and the structure of the RAF. Buback's son Michael for years has researched his father's murder and has always believed that Becker was protected by German authorities.
"For my wife, Elizabeth and myself it has become a certainty that the perpetrators on the motorcycle were not punished for their crimes, and that there was a protective hand shielding one RAF woman terrorist," he said in an interview with German weekly Die Zeit.
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