Updated 5:10 p.m. ET

The Metropolitan Museum of Art delivered an ancient vase by courier to Manhattan's district attorney last week. The DA had issued a warrant for the Greco-Roman vessel on July 24, citing "reasonable cause to believe" the museum was in possession of stolen property.

The vase handover was first reported in The New York Times on Monday.

The terra cotta vessel, which dates to 350 B.C., is what's called a krater: a large mixing bowl used to dilute wine with water. The contested krater bears the image of Dionysus, the god of wine and theater. (Or, alternately, the god of wine and ecstacy.)

Questions about the vase's provenance surfaced in 2014, when The Journal of Art Crime published an article by forensic archaeologist Christos Tsirogiannis, in which he offered evidence the vase had no collecting history prior to 1989, and it matched photos in possession of a convicted art dealer. As a result, he argued, the Met should return the vase to Italy.

Tsirogiannis wrote that the item was likely illegally excavated after 1970, when UNESCO prohibited illicit trade of cultural property.

"When I sent American police the information, they immediately told me that this was 'a great case,' " Dr. Tsirogiannis told the Times. "It was abundantly clear that this rare object had been stolen." He told the newspaper his evidence suggests looters excavated the item from a grave site in southern Italy in the 1970s.

A museum spokesman told the Two-Way the Met had tried to resolve the issues surrounding whether the vase was legally exported since the questions first arose in the 2014 article.

"The Museum has worked diligently to ensure a just resolution of this matter," Kenneth Weine, museum spokesman, said in a statement. "Upon the publication in 2014 of an image of the piece, the Museum began reaching out to the Italian Ministry of Culture – which is in keeping with prior agreements we have with the Italian government. When the Manhattan DA contacted The Met in recent months, we immediately took the piece off display, and last week delivered it to the prosecutor's office."

"The Museum is always committed to working with government partners to resolve an issue regarding an item in our collection," Weine added.

The museum says it paid $99,000 to buy the item from Sotheby's in 1989. The museum provided no further information on the item's acquisition or provenance; Sotheby's told the Times it was not aware of any issues with the piece when it was sold.

The DA's office says that based on similar instances in the past, the next step in the process is sending the vase back to Italy.

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