BERLIN — The leader of an anti-immigrant movement that has attracted tens of thousands of supporters and upended political debate in Germany stepped down on Wednesday after he was found to have posted an online image of himself as Adolf Hitler, after weeks of denying any Nazi sympathies.
In the photograph, the leader, Lutz Bachmann, has his dark hair combed straight and severely parted above his right temple and wears a toothbrush mustache, closely resembling Hitler. The image was found on Mr. Bachmann’s Facebook page and appeared on the front page of the mass-circulation newspaper Bild on Wednesday. It soon went viral on social media sites.
The issue is a sensitive one in Germany, and Chancellor Angela Merkel and other high-ranking officials have repeatedly denounced the anti-immigrant movement, widely known by its German acronym Pegida, which stands for Patriotic Europeans Against the Islamization of the West.
The controversy broke out even as the movement called on supporters to turn out on Wednesday in large numbers at an anti-immigration rally in the eastern city of Leipzig. The group, which has largely been confined to Dresden in eastern Germany, has grown a few offshoots, which are increasingly countered by larger marches throughout Germany in support of immigration.
Mr. Bachmann, 41, told Bild that he was stepping down from the movement’s leadership. Earlier in the day, he declined to comment on the image when reached by telephone. Nor would he address another exchange on social media in which he is quoted as having referred to immigrants as “scumbags,” “stupid cows” and “trash.”
Dresden prosecutors said they were investigating whether there were sufficient grounds to bring charges against Mr. Bachmann. German law forbids the display of Nazi symbols and punishes incitement and hate speech.
“Hitler photos, racist slogans, now we see what is really behind Pegida’s middle-class facade,” Sigmar Gabriel, Ms. Merkel’s deputy chancellor, told Bild, deriding the group for posing as defenders of the people while harboring Nazi sentiments.
“Anyone involved in politics who dresses up as Hitler is either pretty much an idiot, or a Nazi,” Mr. Gabriel said.
On Wednesday, Mr. Bachmann’s profile picture on Facebook had been changed to an image of Charlie Chaplin as the Great Dictator, from the 1940 film that parodied Hitler, with the comment, “He can do satire ... not Lutz!”
Mr. Bachmann told Bild that he had posted the Hitler photo to coincide with the release of an audio version of a satirical book by Timur Vermes, a German writer, called “Er Ist Wieder Da,” or “Look Who’s Back,” in which Hitler returns to Berlin in 2011. “One has to be able to sometimes make fun of oneself,” he told the paper.
The surprising strength of the Pegida movement has dominated German political debate since late December, when the group attracted more than 10,000 people to its weekly marches through Dresden.
The authorities in Leipzig said some 35,000 people filled the city streets Wednesday night, with those marching for tolerance outnumbering Pegida’s supporters. Pegida’s primary goals are limiting the influx of immigrants, protecting the country’s Judeo-Christian heritage and rejecting so-called hate preachers of any kind. Followers also rail about foreigners’ living off German taxpayers.
Chancellor Merkel and her government have repeatedly warned Germans against following Pegida, questioning the motives underlying its anti-immigrant message.
Pegida’s leaders have largely avoided talking to the news media, and advise their followers to do the same, contributing to an air of mystery about the organization’s origins.
Mr. Bachmann was one of the more visible members of the leadership. Last fall, as the marches began, the local newspaper Sächsische Zeitung reported that Mr. Bachmann had a criminal record: convictions for 16 burglaries, driving drunk or without a license and dealing in cocaine. The newspaper also reported that he had worked as a publicist for nightclubs at one point.
Interviewed last month before one of the Monday evening marches in Dresden, Mr. Bachmann was asked about his criminal past and whether it accorded with his concerns that immigrants were bringing crime to Germany. Addressing the marchers, he said, “I, too, have a previous life,” adding, “If it is better for our cause, I am ready to step out of the unwanted spotlight.”
Pegida has sought to play down allegations of links to the far right, insisting that it is a grass-roots movement of concerned citizens.
It has also sought to play down the reports that Mr. Bachmann has a criminal record, with Katrin Oertel, another leader, saying on national public television that everyone deserves a second chance.
It was not clear if that belief would withstand the uproar caused by the publication of Mr. Bachmann’s Hitler photo.
The march in Leipzig on Wednesday night was organized after the German authorities prevented Pegida from holding its regular weekly march in Dresden on Monday because, they said, Mr. Bachmann had been the target of a terrorist threat.