An exhibit featuring works by the tormented Italian painter Amedeo Modigliani closed three days ahead of schedule after Italian prosecutors alleged that 21 of the 60 or so works on exhibit were possible fakes. Three people are under investigation including the curator of the show, which opened at the Palazzo Ducale, one of the main exhibition spaces in Genoa, Italy, in March.

The investigation began on the instigation of Carlo Pepi, an art collector and Modigliani connoisseur, who saw one of the images from the exhibit online and asserted that it was a “shameless fake, created 20 years ago.” An examination of the catalog suggested that the exhibit was “full of fakes,” he said in a telephone interview. He approached Italy’s carabinieri art theft and fraud squad, as well as journalists with a national news agency, and eventually prosecutors picked up the case. Mr. Pepi did not see the Genoa exhibit. “I would never go to see such eyesores,” he said.

An independent Modigliani expert engaged by the Italian art investigators backed up Mr. Pepi’s evaluation, and a second expert employed by the prosecutors is now examining the contested works.

Investigators declined to comment on the case because it was ongoing. Rudy Chiappini, the curator of the show, who is under investigation on several counts including fraud, defended his actions, noting that all the paintings and sketches on exhibit had been “accepted until now without reservations by the international scientific community,” he said in a statement. The works, he noted, were all well known and documented.