Horst Mahler (born 23 January 1936) is a German former lawyer and political activist. He once was a far-left militant and a founding member of the Red Army Faction before later switching to neo-Nazism. Between 2000 and 2003, he was a member of the far-right National Democratic Party of Germany. Since 2003, he has repeatedly been convicted of Volksverhetzung ("incitement of popular hatred") and Holocaust denial, and he served much of a twelve-year prison sentence. In April 2017, Mahler was ordered back to prison for a further three and a half years.
https://en.wikipedia.org/wiki/Horst_Mahler