The Tarbosaurus sale attracted a bid of more than $1 million, but the suspicions of the Mongolian authorities sparked a long legal battle and federal investigation. U.S. authorities froze the sale, and after a lengthy custody battle, the specimen was returned to Mongolia in May 2013.
Eric Prokopi, a self-described commercial paleontologist who imported the dinosaur, pleaded guilty to criminal charges that he smuggled the skeleton and other fossils into the United States. In June, Prokopi was sentenced to three months in federal prison.
The other Mongolian fossils forfeited by Prokopi during the case were returned in the July 10 ceremony, including a second Tarbosaurus, oviraptors and skeletons of the duckbilled, plant-eating Saurolophus angustirostris.
Federal authorities also returned fossils that had been forfeited by Christopher Moore, a onetime business partner of Prokopi in the United Kingdom, including a third Tarbosaurus, skeletons of a rooster-like Gallimimus dinosaur and a nest of fossilized eggs, all looted from Mongolia.