Should the rains hold off, investigators are expected to return to rural San Joaquin County today to pull aside their tarps, descend 45 feet into the earth and resume their painstaking search for human remains.

Already, their tedious archaeological digs have unearthed more than 300 bones or bone fragments at three sites in Calaveras and San Joaquin counties, the most fruitful of which was an abandoned well east of Linden.

The discoveries could confirm what many have long suspected: The carnage left in the wake of notorious "Speed Freak Killers" Loren Herzog and Wesley Shermantine far exceeds those victims known to date.

It could be weeks or even months before authorities know how many more deaths can be attributed to the boyhood friends whose methamphetamine-fueled crime spree over two decades landed both in prison.

In the meantime, authorities have vowed that the digging will not stop until the bones stop appearing.

"We'll go as deep as we can to retrieve all of the remains," said Deputy Les Garcia, spokesman for the San Joaquin County Sheriff's Department.

The evidence has been piling up since Thursday, when sheriff's investigators, guided by a map drawn by Shermantine from death row, searched two San Andreas sites and the well outside Linden. At one San Andreas site, they unearthed a human skull that preliminary results indicated is that of Cyndi Vanderheiden, a 25-year-old woman who disappeared in 1998. At another, they found a skull fragment and teeth likely belonging to 16-year-old Chevelle Wheeler, who disappeared in 1985.

Shermantine eventually was convicted of murdering Vanderheiden, Wheeler and two others. He has maintained his innocence, pinning the blame on Herzog.

In 2001, Herzog was convicted of three killings, but the conviction was overturned on appeal. He ultimately pleaded guilty to voluntary manslaughter in Vanderheiden's death.

Paroled last year, Herzog hanged himself inside his trailer last month, reportedly after Sacramento bounty hunter Leonard Padilla told him Shermantine was about to lead authorities to the bodies.

Shermantine has been communicating with Padilla for years, as well as writing letters to Stockton Record reporter Scott Smith. In a recent letter to Smith, Shermantine drew a map he vowed would lead investigators to Herzog's other victims.

Padilla told The Bee he believes the well being excavated is not the one Shermantine was pointing toward – and that there is another well nearby that holds a dozen bodies.

"The map he drew is kind of confusing," Padilla said. He later added: "There's more bodies in Calaveras and definitely more bodies up there (near Linden)."

Shermantime has not indicated the identities of those victims, and the Sheriff's Department is asking people who believe their loved ones might have been victims of Herzog and Shermantine to call a hotline. Garcia said only people who disappeared before the duo's arrests in 1998 and 1999 would be relevant to the investigation.

Forensic experts said investigators have a tough job ahead.

"It's an interesting case," said Dennis Dirkmaat, director of the applied forensic sciences department at Mercyhurst University in Erie, Pa. "It does pose some difficulties there in the recovery."

Handling buried remains is more like conducting an archaeological dig than processing a typical crime scene. Soil must be dug up in layers and sifted carefully, and bones – sometimes just fragments – must be cataloged and matched.

"It's kind of done inch by inch," said Lawrence Kobilinsky, chairman of the science department at John Jay College of Criminal Justice at the City University of New York. "It's done very slowly and very carefully."

In the well, investigators also have unearthed shoes, jewelry, a coat and car parts, items that could be key evidence – or red herrings. Authorities noted that the area appears to have been a popular dumping ground.

Identifying who the bones belong to will be an arduous task, one that starts with piecing together the bodies. "It's a nightmare, it's a very tough job, but I think it can be done," Kobilinsky said. "And it will ultimately come together through DNA."

As rain fell in San Joaquin County on Monday, investigators scrambled to preserve their scene with tarps and tents, Garcia said.

A few miles away, cows paid no attention to the news trucks lined up on Escalon-Bellota and Flood roads. A Sheriff's Department volunteer who stood watch over the road closure said the excavated well was on private property a few miles east on Flood Road.

The gruesome scene sits about six miles from where the killers grew up. Several business owners in town declined to be interviewed Monday, saying that Herzog's parents were customers – the family still lives in Linden – or that they knew the property owner where the remains were found.

"It's a small town, everyone knows everyone," said one woman, who declined to give her name.

Outside a Mexican restaurant, Linden High School student Thomas Mayo ate a burrito with two classmates. He said the weekend's news was what "everyone is talking about at school."

"My parents went to school with both of them," said Case Samuel, a 16-year-old student at Linden High, referring to the killers.

Samuel, whose family owns a piece of land near the well, described the findings as "kind of creepy."

"And it's ironic," he said. "They were up there the whole time, right in our backyard."

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