Hans-Georg Maassen was once in charge of hunting down neo-Nazis in Germany.
Now he is being investigated for suspected right-wing extremism by the intelligence agency he headed until 2018.
Mr Maassen has published a letter from the Office for the Protection of the Constitution (BfV) confirming that he is under investigation.
The agency says it can’t comment on individual cases because of strict personal data protection rules.
Mr Maassen said on X, formerly Twitter, that the letter did not contain “substantial proof that the investigation was justified,” adding that the government was afraid of him.
He accuses the centre-left interior minister Nancy Faeser of using the intelligence services to fight political opponents.
In the letter, security officials cite Mr Maassen’s apparent belief in far-right and antisemitic conspiracy theories, his anti-migrant rhetoric and an alleged sympathy for the far-right Reichsbürger movement, members of which were arrested in December 2022 after a suspected failed coup.
As head of domestic intelligence, Mr Maassen was accused of downplaying the threat of the far right.
Over the years, he became increasingly vocal about the supposed dangers immigrants posed to German society, and his ferocious comments on social media turned him into an icon for the radical right.
In 2018, he was forced out of office – officially sent into “early retirement” – after he appeared to doubt the veracity of a video showing xenophobic far-right violence at a street festival in the eastern city of Chemnitz.
Since then, his comments have become more extreme. In an article entitled “Chemotherapy for Germany,” he compared migrants to cancer.
Experts say Mr Maassen appears to have become “radicalised” – ironic for the ex-boss of an agency in charge of fighting radicalisation.
He has also now confirmed that his new right-wing political party, the Values Union, which he launched at the end of January, would be happy to work with the far-right AfD to get into power after key upcoming regional elections.
In an interview given to the German news agency DPA, he stopped short of saying that his party would aim to form a coalition with the AfD. But he confirmed that he would co-operate on individual draft laws in parliament and would have no problem relying on the far right to get into power.
This would contradict the approach taken by all other political parties to reject cooperation with the AfD – the so-called “firewall”. The Values Union is still a small, fringe movement. But Mr Maassen’s willingness to break the longstanding taboo against working with the radical right shows how German politics is changing.
Some members of the Values Union attended a now-notorious meeting in November at a lakeside hotel near Potsdam. During the meeting, which was also attended by high-ranking AfD members, participants discussed plans to stage mass deportations of migrants and people of non-German ethnic backgrounds.
Ongoing mass demonstrations across Germany were trigged by the meeting becoming public knowledge last month. On Saturday, another large protest against the far right will be held in Berlin. The slogan: “We are the firewall.”