The director of the National Museum of Slovenia, Pavel Car, has been forced to step down as he is investigated for organizing an exhibition of works critics say were forged.

Some of the works on loan were allegedly acquired from the late Josip Boljkovaca, who served as Croatia’s first internal affairs minister from 1990 to 1991.

The Boljkovac family, who has not responded to a request for comment, loaned the museum 160 works alleged to have been made by Pablo Picasso, Edgar Degas, Henri Matisse, Henri de Toulouse-Lautrec, Joan Mir, Joseph William Turner, Edvard Munch, Kazimir Malevich, Marc Chagall and others. 

If authentic, experts believe the collection would be worth over $1 billion. 

“These are clear forgeries… you don’t need to be an art history expert to notice it,” Brane Kovič, an art historian, told the news website N1 last week. 

Car was forced to step down mere hours before the show was set to open due to accusations that he accepted the loan without conducting proper due diligence, he faced mounting criticism by Slovenian art experts. 

The Slovenian minister of culture, Asta Vrečko, said the response came after the ministry received several concerned letters last week, and that a heated public debate on the planned exhibition had taken place. The ministry convened a special meeting before it was set to open, with the relevant experts reviewing documentation associated with the loan, the minister said. 

The Guardian reported on Friday that Slovenian police have launched an investigation into the scandal. 

Car is alleged to have said at the ministry meeting that he had seen the paintings’ authenticity certificates, but admitted that more could have been done to look into the catalogue raisonné of each artist, which is considered standard due diligence. 

“Nothing is as sad as an empty museum,” he told the news outlet 24 soon after the scandal broke. 

The National Museum of Slovenia and Pavel Car did not immediately respond to requests for comment.