Some 21 paintings in an exhibition of works by famed modernist Amedeo Modigliani (1884-1920) were seized by Italian authorities as part of an investigation into their authenticity.

Displayed at the historic Doge’s Palace (Palazzo Ducale) in Genoa, the works were first called into question by art critic Carlo Pepi last winter. The exhibition, reportedly organized by a collaborator, was set to end Sunday but closed three days early. More than 100,000 people visited the show since March.

Three people, including the curator, are under questioning. The Doge's Palace said in a statement that is “offering maximum collaboration” with investigators.