Major art collector and business tycoon José “Joe” Berardo has been arrested in Portugal over allegations of being involved in a multimillion-dollar fraud plot.

Berardo was arrested on June 29 by the Polícia Judiciária in Lisbon. He is in custody under suspicion of defrauding the Portuguese state-owned bank Caixa Geral de Depósitos, commonly called the CGD.

According to the Polícia Judiciária’s website, a major investigation is ongoing into money laundering and tax fraud against several Portuguese banks. Police said they have searched 51 premises for evidence, including private residences, a banking institution, and a lawyer’s office.

The 76-year-old businessman, who is a prominent collector of modern and contemporary art and who founded his own museum in Portugal, was detained alongside his lawyer. According to Reuters, Berardo is expected to appear before a judge in the next 48 hours.

Police are looking into “an economic group” that allegedly breached contracts with the CGD, as well as two other financial institutions, Novo Banco and Portuguese Commercial Bank. The three banks filed a joint lawsuit in 2019, claiming losses of a billion euros ($1.2 billion).

The CGD lost €439 million ($521 million), according to the allegations.

Berardo also faced trouble in 2019, when the collection of his Museu Coleção Berardo was handed over to the three banks to offset their losses. Until the, his artworks were formally owned by a company called the Berardo Collection Association.

The museum collection, which opened to the public in 2006, includes 1,000 works by 500 modern and contemporary artists, including Willem de Kooning, Jackson Pollock, Cindy Sherman, Pablo Picasso, Joan Miró, and Piet Mondrian.

After an agreement Berardo signed with the Portuguese government in 2006, he lent works from his collection to be shown in Lisbon, where some of them remain.The agreement remains in force until 2022. 

The Portuguese culture ministry did not immediately respond to a request for comment.