A few weeks before Monday's terror attack in Berlin, German agents arrested one of their own -- a 51 year old man who was charged with passing on information to Islamist terrorists.


Even though he had been working at Germany's domestic intelligence agency only since April, the man, who was assigned to monitor Islamic radicals in German cities, was working for the very people he was supposed to keep under surveillance.


German Chancellor Angela Merkel -- who welcomed refugees fleeing the civil wars in the Middle East -- will be under severe pressure from her political rivals after the Berlin attack.


At least 10,000 Salafists -- Muslims who observe a strict version iof Islam -- live in Germany, at least a sixth of whom are considered likely terrorists.