The Hague (AFP) - Dutch police were on Friday investigating the projection of a laser message on the Anne Frank House in Amsterdam, condemned by the museum as an "anti-Semitic and racist" act.
The message referenced a far-right conspiracy theory that the teenage Holocaust victim was not the author of her famous diary, and images of the projection were shown on a private US Telegram channel.
"It happened this week, we were notified and we are investigating it," an Amsterdam police spokesman told AFP, declining to give further details.
The Anne Frank House Museum, which preserves the canalside house where the Frank family hid from the Nazis during World War II, expressed its "shock and revulsion".
The museum, which receives around a million visitors a year, told AFP it had "reported the incident to the police" and was in contact with the city council and public prosecutors.
It said the projected message read "Ann Frank, inventor of the ballpoint pen" -- referring to false claims that the diary was partly written with a type of pen that only came into use after the war.
The claim is based on the discovery of several sheets in ballpoint found among Anne Frank's papers in the 1980s, but which were in fact left there accidentally by a researcher in the 1960s, Dutch media said.
The museum said it found out the message was projected on its exterior for several minutes on Monday evening after the footage appeared in a "hate video" on Telegram.
"With the projection and the video the perpetrators are attacking the authenticity of Anne Frank's diary and inciting hatred.It is an anti-Semitic and racist film," the museum said.
Amsterdam Mayor Femke Halsema condemned the incident as "pure anti-Semitism".
The Jewish teen and her family hid for two years in a secret annexe to the canalside house after the Nazi occupation of the Netherlands during World War II, but were captured in a raid in 1944.
Anne and her sister died in the Bergen-Belsen concentration camp in 1945, but her diary, found by her father Otto, became one of the most haunting accounts of the Holocaust, selling some 30 million copies.
In January, Dutch police said they were investigating the projection of racist slogans on Rotterdam's Erasmus Bridge during New Year's festivities.