Police have arrested a suspected violent left-wing extremist leader in the eastern German state of Thuringia. He is believed to be head of the Leipzig group associated with an already convicted student known as Lina E., security sources told dpa on Friday. They said that the arrest was an intelligence-led operation, and that they had been on the man’s trail for some time. German federal prosecutors and the Saxony police force said the man is suspected of having participated in several politically motivated physical assaults, and of being a member of a criminal organization. According to the in…