WILKES-BARRE - At the foot of a gentle slope dotted with small American flags, a backhoe scraped at the coarse soil until it hit stone.

A few dozen people helped haul the lid of a heavy vault from the cemetery dirt. Beneath it lay a metal casket.

Inside the casket was an autopsy bag. And inside the autopsy bag was the body of a woman, found dead, doused in sulfuric acid, and wrapped in a blanket on a lonely stretch of I-80 in Luzerne County nearly a half-century ago.

Dr. Erin Kimmerle, a trowel shoved into her back pocket, climbed out of an open grave a few feet away and walked over to watch as investigators drilled through the metal casket and lifted its contents into a white body bag. Behind her, the backhoe was already digging at a third grave.

Kimmerle, a forensic anthropologist from the University of Florida, had traveled to the heart of Pennsylvania's coal country Monday for a task she knew might prove futile: exhuming the bodies of four nameless homicide victims and subjecting them to DNA and other evidence testing in the hopes that they might be identified and their killers found.

She was there at the behest of Cpl. Tom McAndrew, a homicide investigator for the state police, who, several years ago, caught the 1973 case of the I-80 victim. The odds of solving so cold a case are thin: "Maybe one in 10,000," he guessed. But exhumation was the only way forward.

"We can't apply current, modern science unless we dig them up," McAndrew said.

But what McAndrew really wants is to stop having to dig those bodies up at all. He's part of an increasingly vocal group of law enforcement officials pushing for laws that would standardize the way coroners and police deal with unidentified bodies.

In most states there's no law, he said, "telling [coroners] that they have to get DNA samples, and keep dental records, and save hair," or a mandate for coroners to enter details about an unidentified body into NAMUS, the federal database that tracks missing people and unidentified bodies, cross-checking the lists for matches.

Many agencies, of course, do this on their own. In Philadelphia, DNA evidence has been saved for nearly all of the 49 unidentified bodies found in the city over the years and listed on NAMUS. The Philadelphia Police Department also submits information to federal databases on every missing person in the city.

In general, Pennsylvania officials are "very progressive" when it comes to working with NAMUS, even without a law requiring them to do so, said Todd Matthews, the database's director of communications and case management.

But of the estimated 40,000 unidentified bodies across the country, only 13,986 have been entered into NAMUS since it was launched in 2007.

A name has been put to just over 2,000 of those bodies.

"The best thing the public can do for us is letting us know what we don't know," Matthews said. "It's sad to have to pass a law to make that happen, but maybe you do."

The victims exhumed this week in Luzerne County were found long before NAMUS's creation, long before DNA testing was even a concept. Now, that evidence will be entered into the database - DNA from the woman in the blanket on I-80; from the man with a pinkie ring found near a fishing hole in 1979; from the woman dumped nude on I-81 in 1970; and from the last body unearthed on Monday, that of a newborn boy found in a landfill in Larksville in 1980.

The county had buried him in an unmarked grave in a small cemetery at the end of a winding road. Locals later raised money for a headstone, placed in the approximate vicinity of the grave.

Kimmerle and her team dug for some time before they hit the tiny autopsy bag. It was placed in a coroner's van and whisked off to a forensic unit, where Kimmerle, McAndrews, and other investigators would be spending the next several days examining the bodies, submitting what evidence they found, and hoping against the odds.

"It's a privilege, really," Kimmerle said. "It's not the biggest problem in the whole world - but when you're missing your child or parent, that is your whole world. And we try to make that difference."