An informant working with German police encouraged suspected jihadis to carry out attacks and had strong links to terrorists, according to reports.
The informant is accused of inciting terrorism by allegedly trying to get people to commit attacks in Germany rather than travel to Syria.
According to a report, lawyers of several terror suspects have claimed the informant pushed their client to carry out attacks, reports The Local.
"Let's kill those non-believers. We need good men to do these attacks here in Germany," he allegedly said, according to lawyer Ali Aydin.
The North Rhine-Westphalia police, where the informant worked, did not respond to the allegations made in a report seen by German broadcaster ARD.
The suspect is also accused of having a strong connection to Anis Amri, the terrorist who killed 12 people after using a truck to plough into pedestrians at a Christmas market in Berlin in December 2016.
German authorities were recently condemned for a series of failures while observing Amri before he carried out the terror attack in the Germany capital.
Bruno Jost, a former prosecutor appointed by Berlin's state parliamentary inquiry into the market attack, ruled it "highly likely" Amri could have been detained by German police last summer.
In the damming report, it was found that Amri was meant to be observed by German authorities for for six months between April and October 2016, but the surveillance only lasted six weeks— a decision that Jost said he "couldn't comprehend".
Police also had enough evidence to arrest him on drugs and forgery allegations, but not for radical Islamic activates, the report added.