About three dozen people hovered around a large patch of grass Monday morning at Maple Hill Cemetery in Hanover Township, two hours north of Philadelphia. Some wore gloves, others held shovels or worked heavy equipment.

The group of state police and forensics specialists was digging three different holes in the midst of exhuming three bodies. One person used a drill to open up a wooden coffin removed from the ground.

"These people are in graves without headstones," said Cpl. Thomas McAndrew with the Pennsylvania State Police. "They're basically forgotten is really what it comes down to."

There are some 40,000 unidentified bodies across the U.S., according to some estimates. Many of them were homicide victims. But even in decades-old cold cases, the tools of modern science and communication could make a difference. That's the hope of McAndrew, who's enlisted outside forensics expertise to revisit the mysteries of nine Jane and John Doe cases throughout the state.

McAndrew, a homicide case veteran, estimates there are about 500 cold cases in his jurisdiction. That includes a black woman who was discovered by a motorist on the side of Interstate 80 in 1973. The victim was wrapped in a blanket and doused with sulfuric acid.

"Nobody really knew about the case at our troop headquarters. There was some evidence in storage there," said McAndrew.

The case was closed after three months with no leads. But McAndrew has been thinking about this woman's unsolved story for almost as long as he's been on the force. Back then, investigators didn't have DNA testing and other methods that could reveal helpful clues about an individual's identity.

Now he's hoping to find answers.

"We can't apply current modern science to it unless they dig them up," he said, referring to the woman's grave being exhumed at Maple Hill, along with two other unidentified bodies in that same area.

A rarely used process

Exhuming bodies is really rare. There's not much money for it. McAndrew estimated this visit cost a few thousand dollars. The last time he was involved in an exhumation was about seven years ago. He recalls that years ago, however, authorities outside Reading exhumed and successfully identified the bodies of two Philadelphia teens who went missing in 1968.

Thinking back to that 1973 cold case, he recently reached out for help to to Dr. Erin Kimmerle, a forensic anthropologist from the University of South Florida and director of the Institute for Forensic Anthropology and Applied Science. She was then able to work that case and eight others in Pennsylvania into a grant from the National Institute of Justice.

"It's really a rights issue for families to know what happened and to have the remains back," said Kimmerle, who is widely known for leading a team that recently recovered several dozen bodies that were buried at the Dozier School for Boys in Florida. "That's really what it's about for us. It's a tremendous gift to give to be able to make those identifications."

Once the remains have been recovered, Kimmerle uses DNA and chemical testing to find out more about the individuals.

"The isotope testing is a way to answer the question of where somebody comes from, and basically if they migrated or lived in different places in their life," she said. "It's a way to track someone's mobility in a broad sense. So we look at teeth and bone and say, 'Is that consistent or different? Is the person born locally, or did they come from some place else?'"

That can be useful information for investigators and the public. But even with modern science, challenges remain in identifying a body. Even today, an estimated 1,000 bodies a year are never identified, according to Kimmerle.

McAndrew stresses that the National Missing and Unidentified Persons system, or NamUs, helps match unidentified bodies with missing people. But for that to work, information about the missing people and unidentified bodies must be entered into the database in the first place. That's voluntary in most places for medical examiners and law enforcement, said McAndrew, though New York and other states have recently changed that.

"I can tell you first hand that a lot of law enforcement aren't even aware of NamUs, and it's been around for over a decade," he said.

Thirty-six years later, Luzerne County still mourns an infant

After the group exhumes the three bodies at Maple Hill, everyone heads to another small Catholic cemetery in nearby Courtdale. It's in a well-kept clearing, hidden up a windy, wooded road behind the town's municipal building.

"This is a story that Luzerne County knows very well," began District Attorney Stefanie Salavantis, who was at the site. "There are still people in Luzerne County that remember that baby every single year and pay respects to that child."

In 1980, a worker discovered the body of an unidentified baby who'd been dumped in a landfill. The tiny body was later buried in the Courtland cemetery.

The crew spent several hours exhuming the remains of the baby. Kimmerle said they weren't sure exactly where it was located, so they took extra care during the process, removing soil with hand-held tools.

"There had been a coffin but it was deteriorated, so were some nails and there's a stain in the soil where the wood had been decomposed and leaves essentially a black outline where the coffin had been," she said.

Kimmerle said that's typical when so much time has passed, but because the remains had been in an autopsy bag, she's hopeful they'll be able to extract DNA and gather information about the mother's origins.

Kimmerle admitted that successfully matching someone is hard, but she's optimistic. She's already had three successes at identifying bodies in Florida this year.

"The way to think about it is if someone is buried and there's no DNA on file, and no face for the public to see, there's no hope for identifying them," she said. "So this is about putting everything science has to offer toward it, to get the best chance of identification."

While testing could help with the mystery this child and others, McAndrew said that the actual chances of solving cold cases are small.

"I'd say maybe it's a one in 10,000 shot, but it's better than nothing, right?" he said. "If we didn't do this it would be 0 in 10,000."

The waiting begins

For the next round of testing, the bodies will go to the medical examiner's office.

It could be months, said Kimmerle, before they know if exhuming the bodies pays off in revealing information about them.

According to a state police department press release, other Pennsylvania cold cases involved in the ongoing exhumation efforts include: 

Case 1: 1973 — Two game commission officers found the partially decomposed remains of a female near Fort Indiantown Gap, Union Township, Lebanon County. The victim was nude and covered with green plastic tarps and leaves. She is estimated to have been white and between 13 and 19. A facial reconstruction and chemical isotope testing have been completed.

Case 2: 2013 — A tree-trimming crew discovered a human skull near the West Manchester Mall in West Manchester Township, York County. This led to the discovery of additional skeletonized remains. It is estimated that the remains are that of a white, Hispanic or Asian male, between 30 and 50. It is estimated that he had been at that location approximately three to 10 years. A facial reconstruction and chemical isotope analysis have been completed.

Case 3: 1994 — Workers doing a mine reclamation project discovered a human skull in a wooded area in Sugarloaf Township, Luzerne County. Additional skeletonized remains were then found. The victim is believed to be a white female between 34 and 47. A facial reconstruction and chemical isotope analysis have been completed.

Case 4: 1976 — A teenage boy who was playing along the banks of the Lehigh River in East Side Boro, Luzerne County, found the remains of a pregnant female. The victim had been sexually assaulted, dismembered, placed in three suitcases and thrown off of an Interstate 80 bridge. She was white and  between 17 and 21. A facial reconstruction and chemical isotope testing have been completed.

Case 5: 2011 — A pedestrian walking along Route 191 in Paradise Township, Monroe County, discovered the remains of a male wrapped inside four black garbage bags. It was estimated that the victim was killed within two months of being discovered. Chemical isotope testing has been completed.

Case 6: 1973 — A motorist found the partially decomposed remains of a black female on the side of Interstate 80 westbound in Black Creek Township, Luzerne County. The victim was wearing blue-green shorts, a pink blouse with lace trim, and blue and green slippers with a floral design. She was wrapped in a blanket and doused with sulfuric acid.

Case 7: 1970 — The nude body of a black female was found along Interstate 81 southbound near Nuangola, Rice Township, Luzerne County.

Case 8: 1979 — The partially decomposed remains of a white male were found by two men who were walking to a fishing spot. The victim was estimated to be between 25 and 40, and he was wearing a sterling silver bracelet with "Vedon" on the clasp and a 14-karat gold serpent design ring on his pinkie finger.

Case 9: 1980 — A landfill worker found the body of a newborn baby boy among trash in Larksville Borough, Luzerne County. He was white and believed to have been born 24 to 72 hours prior to discovery.