According to the latest report by Hans Leyendecker and Georg Mascolo in the Süddeutsche Zeitung, on 14 December, five days before the attack, security authorities issued “the latest version of a personal profile containing everything they knew about Amri.” The document describes “a man whose résumé is very similar to that of former assassins in the service of the terrorist group Islamic State,” according to the two investigatory journalists, who have close links to sources in secret service circles.
According to Leyendecker and Mascolo, the secret services knew virtually all there was to know. The profile describes “the career of a petty criminal who was already in prison in Italy as a youth, and committed a theft in a German asylum shelter. It contains language skills: German, Arabic, Italian, Spanish and French…. It contains the eight identities that Amri used. There are constantly changing domiciles and places of residence. There are several pictures of him.”
The journalists note that Amri may have shared many of these factors with other potential offenders under the surveillance of the intelligence services, but in his case, “the evidence is even more concrete.” For instance, the state police agency in Duisburg described Amri as “a Salafist and radical fundamentalist.” The police department in Dortmund assessed him to be a sympathizer of the Islamic State.
[source : Berlin terror attack suspect was well-known to German intelligence agencies, WSWS, http://www.wsws.org/en/articles/2016/12/30/berl-d30.html, 30th December 2016]