When an Italian magazine published a cover story about a new Leonardo da Vinci painting in 2013, art lovers and collectors the world over were salivating at the prospect of a unknown masterpiece by the famous renaissance artist.

However, the expert cited in the article has now denied that he ever authenticated the painting, the Globe and Mail reports.

“I never attributed this painting to Leonardo,” Carlo Pedretti, Director of the Leonardo center at the University of California, Los Angeles told AP. “I only said it merited more study.”

Meanwhile, the value of the painting has skyrocketed from €95 million, when the existence of the painting was first discovered in 2013, to over €120 million when it was finally located in the vault of a private Swiss bank last summer.

This week, the oil on canvas portrait of the Italian noblewoman Isabella D’Este was seized by Italian police who suspect that it may have been illegally expatriated (see $170 Million Leonardo Da Vinci Seized from Swiss Bank Vault). In a press release the Italian authorities reiterated the painting’s unconfirmed attribution to Leonardo.

Pedretti clarified that he analyzed the painting several years ago after he was contacted by representatives of the owner. He explained that he wrote a letter, which stated that although the painting featured resemblances to Leonardo, more tests were necessary before it could be properly authenticated.

Alessandro Vezzosi, Director of the Leonardo Museum in Vinci, Italy, also disputes the attribution. He told the Globe and Mail that Leonardo may have contributed to the portrait, but it’s most likely that a student completed the majority of the painting. “Leonardo was very interested in his personal research and studies in mechanics and physics. He didn’t have time to stay and work on a painting,” he said.