Manhattan prosecutors, who received the item from the Met after obtaining a warrant for it on July 6, declined to comment on the case. The lawsuit says the district attorney’s office has sent a letter demanding that the Beierwaltes “restitute the bull’s head to Lebanon” because the office believes it was stolen from there.

Reached by phone in Beirut, Sarkis Khoury, head of Lebanon’s antiquities office, said, “We will do all we can to repatriate this item.”

In a statement, the Met said: “Upon a Met curator’s discovery that this item on loan may have been stolen from government storage during the Lebanese civil war, the museum took immediate action. We contacted the Lebanese government and the lender, we took the item off display, and we have been working with federal and state authorities, which recently involved delivering the head of the bull to the Manhattan D.A. upon its request.”

The item has a rich history. According to museum and Lebanese officials, it was first cataloged in 1967 by a Swiss archaeologist excavating the Temple of Eshmun in Sidon, Lebanon. It is believed to be of Greek origin, was warehoused in the city of Byblos, the site of a looting spree in the 1980s.

This is the second time in recent weeks that the Met has been asked to turn over an item to Manhattan prosecutors, though the circumstances are far different in each instance. Last week, the Met surrendered an ancient vase that it bought at auction in 1989 because of concerns that it might have been looted from Italy.

In that case, a forensic archaeologist approached law enforcement officials last May with evidence that the item, known as a krater, had been looted from an ancient grave in Italy. In an interview, he said that he approached law enforcement after becoming frustrated that museum officials had not responded to him about evidence he shared with them in 2014.

But the museum said that several years ago, after reviewing the archaeologist’s evidence, it had contacted the Italian authorities as part of an effort to resolve the ownership of the item. The Met said that those discussions were continuing when Manhattan prosecutors served a warrant on July 24 seeking possession of the vase, which the museum delivered the next day.