Hans-Georg Maassen, the man once in charge of tracking political extremists in Germany, has developed a brash second career on social media since his sacking last year.

Largely delivered on Twitter, Maassen's provocative pronouncements have created another headache for Angela Merkel's Christian Democratic Union (CDU), which is facing an uncertain era after the chancellor's retirement.

Maassen's tweets have also raised questions about how his political opinions may have influenced the direction investigations took during his six years as head of the Federal Office for the Protection of the Constitution (BfV).

Maassen's office, from which he was fired last year by Interior Minister Horst Seehofer, is in charge of keeping tabs on the activities of Islamists, neo-Nazis and antifa groups inside Germany.

Read more: Germany records small uptick in far-right violence

Anti-immigration and climate science

The most controversial of these social media posts came last Monday, when Maassen shared an article by right-wing blog Journalistenwatch claiming that the rescue of migrants by the ship Sea-Watch 3 was effectively a hoax orchestrated by German public broadcaster ARD.

Several media outlets subsequently pointed out that Journalistenwatch was run by the founders of a now-defunct minor right-wing party called Die Freiheit (The Freedom), which itself was under observation by the BfV. It also frequently signals support for the pan-European Identitarian Movement, another far-right group that has caught the attention of the office Maassen once ran.

But while that tweet was subsequently deleted, Maassen seems to have developed a taste for the notoriety his social media presence has triggered.

In the past week, the ex-intelligence chief's tweets have included posting an article denying the climate crisis in Cologne-based tabloid Express, comparisons between the German public broadcasters and the dictatorship-led media of communist East Germany and a cartoon implying that media outlet Der Spiegel mainly contains fairy tales. He also had more criticism of the rescue missions in the Mediterranean:

"Don't let yourself be persuaded that this is about rescuing people at sea," he tweeted on Friday. "These migrants aren't shipwrecked people, and not refugees. They have boarded trafficker boats as would-be foreign immigrants to get brought to Europe by a shuttle service."

Pushing the conservative CDU

There have been many clues to Maassen's political leanings since his departure from the BfV last year, which came after he cast doubt on videos that showed people of immigrant background being attacked in Chemnitz. Seehofer attempted to find Maassen a job in his ministry, but the outcry proved too great for the government.

Maassen's Twitter profile, which is emblazoned with a slogan "Change. Germany can do better," also includes a link to the Werte Union ("Union of Values"), an organization that represents the conservative wing of the CDU and sees its main purpose in reviving what it believes are values that the CDU leadership has lost.

Maassen has become the Werte Union's most prominent public face in the last few weeks, and it has seen an uptick in membership over the past two years. 

Of all the high-profile figures on the right of the CDU (another is erstwhile leadership challenger Friedrich Merz), Maassen has been the most radical in his anti-immigration declarations.

At a Werte Union event in Wernheim, southern Germany, in late June, the 56-year-old sparked another media storm by saying, "I didn't join the CDU 30 years ago so that 1.8 million Arabs could come to Germany." That statement was greeted with cheers from the assembled party members, according to a report in the Rhein-Neckar-Zeitung, and drew plenty of outrage from opposition leaders.

Maassen described his own political position as "not conservative, just realistic," but other signs suggest he is not above political strategy: In mid-June, he gave an interview to public radio station Deutschlandfunk in which he suggested that a coalition with the far-right Alternative for Germany (AfD) was not out of the question in future.

The AfD is currently polling first in some states in eastern Germany, three of which are due to hold elections this fall, putting the CDU under considerable pressure from the right. All the leading figures in the CDU have so far ruled out forming a government with populist AfD, but there are signs that the resolve in the upper echelons of some regional CDU parties is starting to buckle.

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