Berlin authorities have banned the Fussilet mosque, which Anis Amri used to attend. Meanwhile around 460 officers searched 24 locations across the capital city in the early hours of Tuesday morning in a raid linked to the mosque.
Amri had visited the mosque regularly before he drove a truck into a Christmas market on December 19th, killing 12 people, in an attack later claimed by terror group Isis.
Police believe the mosque was a meeting point for radical Islamists who were willing to commit violence. It is also suspected that people inside the mosque collected money for terror attacks in Syria. Participants of Islam classes - mostly Turks and Caucasians - were reportedly radicalized and encouraged to fight with Isis in Syria.
No arrests have been reported thus far.
A motion to ban the mosque had been submitted on February 15th, and the prayer rooms were closed down by the mosque itself a week ago. The mosque has also cancelled its rental contract for the space, according to Berlin interior minister Andreas Geisel.
Investigators on Tuesday searched through apartments, two company offices, and six holding cells in city jails. Geisel said there would be further information about the raids and ban later at a mid-day press conference.
Police had had the mosque under surveillance from a station across from the entrance, including with the use of cameras.
A ban on the mosque has been discussed since 2015. After the December attack, officials moved quickly to implement the ban.