Based on the hair tests, investigators now believe the woman didn't travel any farther south than Salt Lake City, no further east than Wyoming, and traveled mostly in the Northwest, namely Idaho, Washington and Oregon. Park believes he can trace where the woman was during the last two years of her life.

"I'm pretty excited about (Ehleringer's) stuff," Park said.

The next step for the sheriff's office is testing the isotopes in the woman's teeth to determine where she grew up.

Park said the new technology could be used, for example, to track a serial killer. If an unidentified body is found in Utah, but isotopes say the person had been in Florida, Park said it helps law enforcers look for missing persons' reports in that region rather than locally in an effort to identify the individual.

"I don't know if it will ever reach the realm of what DNA did for us, but it could be very beneficial," he said.

But what if a person drinks bottled water that is imported from out of state or even out of the country?

Ehleringer said unless the person is drinking a disproportionate amount of bottled water compared to the rest of their food and drink intake, scientists still should be able to accurately look into that person's travel history.

"On a general basis, the milk that you drink, the soft drinks, the beer, the water you're boiling potatoes with, all comes from the same region," he said.

Ehleringer is no stranger to coming up with new methods to help law enforcement. He previously developed methods using similar isotope techniques that help law enforcers determine whether cocaine and heroin were produced locally or not, as well as in what region counterfeit money was produced.

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E-mail: preavy@desnews.com