The man in his fifties, living in the city of Hamburg attends a local mosque in the northern German city where there is an important Turkish community, local media report.
German security forces and interior intelligence services are investigating the crime and are wondering whether the man acted alone or received instructions for the gruesome assassination.
Neighbors and mosque members told security forces that the man’s behavior had changed before the killing as he developed a long bear and was donning Afghan men’s dress code.
Germany, several countries have been complaining, has become a safe haven for dozens of former ISIS militants who fought in Syria and Iraq.
Morocco has warned the European country against the presence on its soil of former ISIS terrorists.
In March, an investigative report by French television M6 raised the alarm over the presence of former fighters of the terror group who are living freely in Germany.
The M6 flagship program “Enquête Exclusive” showed how ISIS Jihadists managed to slip through the cracks by posing as asylum seekers, and how they ended up being greeted with open arms and offered a safe haven in Germany, because of the dangerous laxity of German authorities.
While ISIS was officially defeated in March 2019 when it lost its last sanctuaries in Syria and Iraq, executioners from the terrorist organization are still on the run.
The criminals branded lone wolves are believed a major threat and can be quickly mobilized by a dormant cell of the global terror group.