German police are hunting down the operator of a Facebook page of the “anonymous” group for criticising migrants.

In the latest crack down on online speech, the anonymous group, who originated on notorious website 4chan, are in the sights of German police. A German branch of the group is now under investigation by authorities who say that either a supporter, or the operator of the group’s Facebook page, is wanted for “sedition” and public incitement of criminal acts, Spiegel Online reports.

The prosecutor in the German city of Erfurt claims that a man named Mario Rönsch is their main suspect in the case. Mr. Rönsch is wanted in connection with spreading hate speech about migrants, as well as for fraud and other crimes. The prosecutor did not go into detail regarding the charges, though noted that the site had been advertising “right-wing” views.

The page “Anonymous.Kollectiv” was shut down earlier this year by Facebook who have been working with German authorities to suppress the pages of people and groups who are critical of the migrant crisis and who express what they consider “hateful” views. Anonymous moved their page to Russian Facebook competitor VK shortly after their Facebook page was shut down.

The page was closed after the group had released leaked documents regarding the German government’s plan to spy on Internet users and curtail dissenting opinions. The leaked documents showed the cooperation of the government with ex-Stasi agent Anetta Kahane and the Amadeus Antonio Foundation who were recently protested by the hipster-right Identitarian Movement in Berlin.

German media reports that the origin of the charges come from disgraced Green party politician Volker Beck who earlier this year was arrested for possession of crystal meth in Berlin. Mr. Beck claimed that the page was behind threats, incitement to crime and defamation against him. The politician supplied authorities with information on the identity of the person behind the posts earlier in the year.

According to German magazine Focus, Mr. Rönsch is the administrator of the Anonymous page, though Mr. Rönsch himself has denied the allegation. In 2014 he took Spiegel Online to court in an attempt to stop them publishing his name in connection with the page.

Mr. Rönsch has also appeared in videos for right-wing magazine Compact which were critical of German Chancellor Angela Merkel. In the video Mr. Rönsch, who is presented as a long time reader of the magazine, calls for the resignation of Ms. Merkel — much in the same way the supporters of the PEGIDA movement popularised the chant “Merkel Muss Weg” or “Merkel Must Go” — though Mr. Rönsch has stated that he would like to see her in prison, as well.

The Erfurt prosecutor said that there are currently three cases open regarding Mr. Rönsch, but none of them can proceed until the police are able to locate his whereabouts.