He is one of the most paradoxical and notorious figures in modern German history: a social democrat lawyer turned leftwing terrorist who went to prison, turned to Maoism and then came out as a far-right nationalist.
Now there is another twist: Horst Mahler, a founding member of the Red Army Faction, was also a Stasi informant.
According to German newspaper reports, the revelation comes from a leaked report by state prosecutors re-investigating the shooting of a pacifist by a Berlin policeman during a 1967 protest.