How the Discovery of 'Sue', the Famous T. rex, Led to an FBI Raid and a Scientist's Prison Sentence

On August 12th, 1990, a truck with a flat tire gave a fossil hunter a little extra time. According to accounts of the day, Sue Hendrickson, a worker with the Black Hills Institute, used the delay to walk the base of some cliffs on the Cheyenne River Indian Reservation in western South Dakota. She found small fragments of bone on the ground, then noticed larger bones sticking out of the rock above her head. It was the last day of the team's summer dig.

The Black Hills Institute is a private company that specialises in excavating and preparing fossils. Its crew had spent the season finding bones of Edmontosaurus, a large plant-eating dinosaur. Its president, Peter Larson, identified what Hendrickson had found as T. rex and ordered extra plaster so the fragile bones could be removed from the cliff safely. Hendrickson and a number of others recovered 250 of the animal's 360 known bones. Most T. rex skeletons are missing around half their bones. The specimen, catalogued as FMNH PR 2081, was named Sue after its finder.

The skeleton is about 67 million years old and is 90 percent complete by bulk and 73 percent by bone count. Scientists do not know whether the animal was male or female. A 2020 study put her age at roughly 33 at death, the oldest T. rex ever studied. Her bones record a hard life: a damaged right shoulder blade, a torn tendon in her right arm and three broken ribs, all of which healed.

The argument over who owned her began almost at once. The Black Hills Institute had permission to dig from Maurice Williams, the putative landowner, and paid him $5,000 for the remains. Williams later said the money covered only access to his land, and that under their agreement Larson was to remove and clean the fossil for a later sale. Because Williams was a member of the Sioux Nation, the tribe entered the dispute too, claiming the bones as theirs.

The land did not belong solely to Williams. It was held in trust by the United States Department of the Interior, so permission was needed before anything found there could be sold. When Williams sold Sue to the Black Hills Institute, both sides unknowingly broke the law.

In 1992 the FBI and the South Dakota National Guard raided the Institute, seizing Sue along with documents and other fossils believed to be tied to the dispute. In 1996 Larson was found guilty of minor customs violations, failing to file currency reports, and minor theft of government property involving small fossils. He was sentenced to two years in federal prison. The courts held that Williams still owned Sue and could do as he liked with her.

Williams put her up for auction at Sotheby's on October 4th, 1997. Many palaeontologists feared a private collector would buy her and take her out of public view. Fossils held privately cannot be freely studied, earlier findings cannot be checked by other researchers, and new technologies cannot be applied to them. For that reason many leading journals will not publish studies of privately owned specimens, even ones lent briefly to museums.

The Field Museum of Natural History in Chicago won with a $7.6 million bid, backed by the California State University system, Walt Disney Parks and Resorts and, perhaps surprisingly, McDonald's. The final cost reached $8.3 million, the most ever paid for a fossil at that point. The record has since fallen twice: Stan sold for $31.8 million to Abu Dhabi's Natural History Museum in 2020, and Gus fetched $50.1 million in 2026, with its buyer not yet disclosed.

Sue has repaid the investment scientifically. She revealed aspects of T. rex and wider theropod anatomy not previously known, and enabled biomechanical models of her arms and neck and studies of how large theropods grew with age. She stands 12.8 metres long and 3.96 metres tall, weighs 14,000 kilograms, and occupies a 5,100-square-foot suite on the museum's upper level, open to researchers and the public alike. Few nearly complete T. rex can say the same.