BERLIN.- The German police are investigating Roger Waters, co-founder of the band Pink Floyd, who has long been critical of Israel, after he performed in Berlin last week wearing a Nazi-style costume like the one he used to critique fascism in “The Wall.”

Waters, who has made anti-Israel statements in the past that many have said cross a line into antisemitism, has successfully fought two attempts by German courts to block him from German concert venues in the past.

The investigation is focused on the costume Waters wore during a rendition of the 1979 Pink Floyd song “In the Flesh,” from their seminal album “The Wall,” in which a rock star imagines himself as a fascist dictator. Similar staging was featured in the 1982 movie “Pink Floyd: The Wall,” featuring Bob Geldof.

During parts of the concerts in Berlin, on May 17 and 18, Waters wore a black trench coat with epaulets and a red armband, according to videos posted to social media and witnesses. Flanked by men dressed in costumes that evoked Nazi storm troopers, he shot a prop machine gun into the audience. Waters has worn similar costumes at concerts outside of Germany for years for the routine, which he has called satire.

Berlin authorities will have to determine to what extent the display of Nazi-like imagery is protected by artistic freedom of expression. In Germany, displaying Nazi symbolism, such as swastikas or SS regalia, justifying or downplaying the Holocaust, and antisemitic acts are illegal.

“Artistic freedom of expression is not a license to incite hatred,” Nicholas Potter, a researcher with the Amadeu Antonio Foundation in Berlin, a group that tracks neo-Nazism, right-wing extremism and antisemitism in Germany, wrote in an email exchange.

“Artistic freedom is often used as an argument to express anti-democratic or hateful views, including antisemitic ones, but that doesn’t always mean it’s applicable — the context is crucial,” he added. Potter attended one of the Berlin shows and wrote about it on the foundation’s news blog.

Waters initially agreed to an interview with The New York Times about the investigation but then declined. A representative wrote: “We are reluctant to comment if the intention is to further sensationalize this fabricated news story.”

A Berlin police spokesperson said investigators would present their findings to the Berlin state’s attorney within the next three months. The state’s attorney will decide whether to indict Waters.

Waters is a vocal proponent of the Boycott, Divestment and Sanctions movement, or BDS, which pushes foreign governments, businesses and performers to cut ties with Israel until it ends its occupation of the territories it captured in 1967, among other demands.

Waters at past concerts has included a floating balloon representing a flying pig, which featured the Star of David. He defended that action, saying in 2013 on Facebook: “Like it or not, the Star of David represents Israel and its policies and is legitimately subject to any and all forms of nonviolent protest.”

In a Facebook post Sunday addressing the controversy around his German concerts, he criticized German lawmakers who condemned BDS, saying they had “enshrined a recommendation to the German people to ‘stand by silent and indifferent’” to the “institutionalized murder" of the Palestinian people by a “tyrannical racist regime,” which he said was Israel.

On giant display boards at the concert, the name of Anne Frank, one of the most readily recognizable victims of the Holocaust, during which Germans killed more than 6 million Jews, was juxtaposed next to the name Shireen Abu Akleh, a Palestinian American television correspondent who was shot by Israeli Defense Forces soldiers during a raid into the West Bank last year.

On Wednesday morning, Israel’s Foreign Ministry posted on Twitter: “Good morning to every one but Roger Waters who spent the evening in Berlin (Yes Berlin) desecrating the memory of Anne Frank and the 6 million Jews murdered in the Holocaust.”

On Wednesday, the Simon Wiesenthal Center publicly called on German authorities to investigate the concert in Berlin. “There are few performers whose anti-Israel vitriol can match that of Waters,” the center wrote in a statement. “Despite his protests to the contrary, Waters has, for years, crossed the line between anti-Zionism and antisemitism.”

Any charges stemming from the concert would come as Germany faces a more general debate about the rise of antisemitism in the country, 78 years after the end of the Holocaust. In addition to an overall increase in the number of antisemitic crimes reported in the country, there were wide-ranging discussions after a group of leaders of cultural institutions published an open letter decrying not just BDS but a parliamentary resolution that declared BDS inherently antisemitic. And an art installation featuring antisemitic caricatures at the Documenta art festival in Kassel last year led to another round of soul searching among cultural elites.

The city of Frankfurt tried to stop Waters from performing at the Frankfurter Festhalle this Sunday, a concert venue partly owned by the city. In November 1938, thousands of Jewish men were taken to the arena after the night of pogroms known as Kristallnacht, before being shipped off to concentration camps. But a judge in Frankfurt backed Waters, who had filed an emergency injunction against the city Monday, citing the constitutional right to artistic freedom and the fact that there was no evidence that Waters would break the law.

In March, the city of Munich determined that it could legally not back out of a contract with the musician for a show, which he played at the Olympic Stadium there last week. Instead, the city decided to allow organized protests outside the venue on the day of the concert.

This article originally appeared in The New York Times.