A Colorado couple has dropped a federal lawsuit that sought to stop the Manhattan district attorney’s office from returning to the Republic of Lebanon an ancient marble bull’s head that prosecutors said had been looted during that country’s civil war.

The 2,300-year-old sculpture had been on loan to the Metropolitan Museum of Art until July when the museum turned it over to authorities after a curator raised concerns about its provenance to Lebanese officials, who requested its return.

The collectors, Lynda and William Beierwaltes, had argued that they bought the artifact in good faith for more than $1 million in 1996. But on Wednesday, the couple’s lawyer, William G. Pearlstein, released a statement that said, “After having been presented with incontrovertible evidence that the bull’s head was stolen from Lebanon, the Beierwaltes believed it was in everyone’s best interest to withdraw their claim to the bull’s head and allow its repatriation to Lebanon.”

In an unusual twist, though, prosecutors said they are now pursuing the return to Lebanon of a second work that they discovered while recently reviewing a profile of the Beierwalteses in an old issue of House & Garden magazine. In a June 1998 special issue, Assistant District Attorney Matthew Bogdanos spotted an antiquity, “an archaic marble torso of a calf bearer,” in a photograph of the Beierwalteses’ home. Mr. Bogdanos said in a court filing that it too had been stolen from Lebanon.