In May 2000, the 42-foot skeleton of a well-preserved Tyrannosaurus Rex went on display at Chicago's Field Museum amid much fanfare. But few of the millions who've seen Sue (named for her discoverer, Sue Hendrickson) in the 14 years since are aware that this once-ferocious dinosaur was embroiled in fierce battle over the custody of its bones that dragged on for the better part of a decade. This fascinating story is the subject of the documentary "Dinosaur 13," directed and produced by Todd Douglas Miller and opening in theaters on Aug. 15.

Based on the book "Rex Appeal: The Amazing Story of Sue, The Dinosaur That Changed Science, The Law and My Life," by Peter Larson and Kristin Donnan, the film begins in the summer of 1990, when a team of paleontologists from the Black Hills Institute in South Dakota including Larson and Hendrickson, found the T. rex fossils and paid landowner Maurice Williams $5,000 for them. Unpredictably, that unleashed a complicated dispute over who owned the bones: the institute, Williams, the Sioux tribe to which Williams belonged, and the federal government, because the property was held in trust by the U.S. Department of the Interior.

The FBI and the National Guard seized Sue's remains in 1992, placing them in storage, and they remained there while a David-vs.-Goliath fight over their ownership played out in the courtroom until as settlement was reached five years later. The skeleton was auctioned off for a record $8.36 million in October 1997, and it took three years to prepare it for display. "Dinosaur 13," it turns out, also traveled a long and complicated road to the screen.

"We started with conducting intensive first-person narrative interviews with everyone involved. At first we decided to dramatize the film with re-enactments and make it more of a docudrama.  But then we were supplied with so much archival footage and press materials that we decided to utilize that instead," says Miler. "In all, there was around 300 hours of footage. Our approach was to go through every second of every frame, sometimes multiple times. We really wanted this to be the definitive story on Sue and her discoverers. So that meant years and years of research and talking with everyone involved in the story, some of whom are speaking for the first time in the film. Mostly everyone agreed to be in the film."

With so much material and a complex story, Miller's biggest challenge was "telling a very complex story that takes place over such a protracted amount of time in under two hours." In particular, he found, "There's no easy way to explain the land/ownership issue in a nutshell.  Basically, dinosaur hunters can dig on either public or private land. The permitting process on public land, as well as the laws and regulations, are ever-changing. The case in our film set a precedent, which is still debated today."

The fact that the paleontologists wound up facing a host of criminal charges — and Peter Larson was even imprisoned — while Maurice Evans profited handsomely is one of the unfortunate ironies of the story and an important thread in the film. "Sometimes when a large, multiple-pronged apparatus is set in motion it's very difficult to stop,” Miller reflects. "Maurice Williams was entitled to the proceeds of the auction because he owned the dinosaur. Whether that is right or wrong is up to the audience to decide."

Surprisingly, Larson isn't bitter over the loss of his beloved Sue. "I've personally never meant anyone with a more positive outlook and attitude on life than Peter Larson," says Miller. With regard to lessons learned from the story, that positivity may have rubbed off. "We're all on the this planet for a very, very short time and we all need to treat each other with care and respect. And the more we learn about the history of past life on this planet the better off we're all going to be as we move forward as a society."

Miller hopes that audiences come away with that appreciation and a little motivation. "We want to get people excited about science and dinosaurs," he says. "Paleontology is one of the greatest fields in all of science, so it's my hope that the film will encourage people of learn more about it."

Related on MNN:

The twisted custody battle over a T. rex named Sue
The fascinating story of a dinosaur's ownership is the subject of the documentary "Dinosaur 13."