Looters who plundered one of Utah's newest troves of dinosaur bones got away with ribs, vertebrae and part of an ancient legbone they had to bust apart to remove. They also stole hidden scientific clues about the life of a young diplodocus dinosaur that roamed the area some 150 million years ago.

"It's like pieces of a puzzle that are now gone," said Scott Williams, collections and exhibits manager at the Burpee Museum of Natural History, the Rockford, Ill.-based institution that has been digging at the U.S. Bureau of Land Management-owned site.

The bones — and the thieves — from the site near Hanksville haven't been seen since the theft last fall. And, odds are, they won't. Stolen dinosaur bones and other fossils snatched illegally from federally owned land often disappear into living rooms, lucrative underground markets or expensive private collections.

But a new forensic technique — something akin to DNA fingerprinting — could give investigators a long-sought tool to track fossil thieves.

Researchers are testing methods designed to match chemical signatures of naturally occuring elements that seep into bones during fossilization with surrounding soil.

The process — which analyzes a group known as rare earth elements — could someday lead to a database of site "fingerprints" used to link bones to looted areas. More work is needed, but early signs are encouraging that the technique could be useful in nabbing those capitalizing on looted fossils, said Dennis Terry, a researcher at Temple University in Philadelphia.

"I really hope we can make use of this to deter the ones out there really trying to make a profit from this," said Terry, who is working on the project with fellow Temple researcher David Grandstaff.

Testing on the technique continues in Wyoming this summer. It has been honed since 2005 at Nebraska National Forest, another hotspot for fossil thieves. So far, results indicate the analysis could tie 85 percent to 98 percent of fossil samples back to their original sites. Terry is also speaking with officials at South Dakota's Badlands National Park about starting a database of the park's most poached sites.

"So often we catch people with fossils in their car or something like that but we can't prove they were collected in the park," said Rachel Benton, a paleontologist at Badlands, which has a long history of fossil poaching.

Fossil theft is a frustrating and all-too-common reality for paleontologists working on federal land who say the objects — aside from being government property — hold irreplaceable information in trying to piece together the story of ancient life.

"We're not making T-rexes any more," said Vincent Santucci, who heads the National Park Service's paleontology programs.

That rarity also feeds high prices. There are legitimately collected fossils taken from private land with permission from the land owner. The complete skeleton of a 150-million-year-old dryosaurus found on private land in Wyoming was put up for auction earlier this year with a minimum price of $300,000.

Illicit artifacts can also fetch a high price, especially complete skulls and teeth.

"People are making a living off of selling resources that belong to the American public," said Scott Foss, who oversees BLM's paleontological operations in Utah, Nevada, Oregon and Washington.

In Utah, which is rife with dinosaur quarries and regularly the source of newly found species, the losses to scientific knowledge can be dramatic, said Jim Kirkland, the state paleontologist. He said he's terrified that vandals will hit a significant site before scientists can meticulously go through it.

"I lose sleep over stuff like that," said Kirkland, who, like other paleontologists, is cautiously optimistic about the new method.

The last survey in national parks found more than 700 instances of fossil theft or vandalism in 1995-98. Similar estimates aren't available for national forests or the BLM.

For paleontologists, there's a sense of inevitability that, once word trickles out about a rich fossil site, it'll be hit by vandals or thieves.

"You can't live there 365 days a year, 24 hours a day," said Brooks Britt, a paleontologist with Brigham Young University who has had several of his sites vandalized.

That's part of the reason why agencies tend not to disclose all of the paleontological sites they know about.

Looters run the gamut from casual visitors who pocket a few chipped fossils to sophisticated operators using professional power tools to swipe items for a lucrative underground market.

Methods differ too. Some are brazen, like three men who yanked a bone out of a visitor center display at Dinosaur National Monument on the Colorado-Utah border or those who tried to dig up 180-million-year-old dinosaur tracks at a BLM site in Wyoming. Several years ago, thieves at Badlands reported a false emergency in another part of the park so they could load up with fossils without fear of a patrolling ranger.

For law enforcement officers, fossil thefts pose a difficult problem. Many are responsible for patrolling millions of acres of public land where dinosaur quarries are remote and the odds of catching someone in the act are exceedingly rare.

At Badlands, rangers are relying more and more on remote cameras and sensors, said Mark Gorman, the chief law enforcement officer.

He and others are also hoping a new law signed by President Obama in March that toughened penalties for fossil thieves will have an effect.

Barbara Beasley, a paleontologist at the forest, said she'd welcome any help to fight poaching.

"Anytime anyone uncovers a fossil, they are very first human to every to see that and attached to that is a major responsibility making sure we do justice to the specimen," she said.