SAN FRANCISCO — The childhood friends killed for the first time less than three months after their high school graduation in 1984. Then they seemingly killed with impunity for the next 15 years, with one man making barroom boasts about their ability to make people disappear.

By the time the hunting buddies were finally arrested in 1999, investigators say the notorious "Speed Freak Killers" killed as many as 20 people during a 15-year spree that terrorized California's rural Central Valley. Some of their victims were left at the scene. Most were never seen again, especially their female victims.

Even after their convictions in 2001, Wesley Shermantine and Loren Herzog steadfastly refused to divulge any burial sites.

Now, motivated by a bounty hunter's promise to pay $33,000 for the location of the missing, Shermantine is breaking a long silence. Family members of the missing hope the new details will lead to the discovery of their loved ones' remains and closure after years of torment. Two victims have already been identified and hundreds of human remains have been recovered over the last several days. More are expected to be found.

"It is a happy occasion," said Paula Wheeler, mother of 16-year-old Chevelle "Chevy" Wheeler, whose remains were tentatively identified Friday after the girl disappeared in 1985. Chevy's portrait hangs in the living room of the Wheeler's Crossville, Tenn., home. The Wheelers intend to have Chevy's remains cremated and displayed at their home.

Shermantine told Sacramento bounty hunter Leonard Padilla that he plans to use the $33,000 to pay $15,000 in court-ordered restitution to victims' families. The rest will buy headstones for his deceased parents and small luxuries in prison like candy bars and a private television set he can't buy because every penny he receives now is used to pay down the restitution debt. Padilla hopes to claim rewards offered by the state of California for information about missing persons thought to be the victims of Shermantine and Herzog.

Using crude maps Shermantine hand-drew in his Death Row cell, investigators have dug up three sites since Thursday that have yielded human remains.

The site of the biggest find is an abandoned well outside the city of Stockton, near the town of Linden, that produced hundreds of human bones, purses, shoes, jewelry and other evidence over the weekend. That raised Joan Shelley's hopes that her 16-year-old daughter JoAnn Hobson will be found.

"I feel they are going to find her," a tearful Shelley told The Associated Press in a phone interview from her Manteca home. JoAnn disappeared in 1985, and investigators have long suspected Shermantine and Herzog in the girl's abduction and murder. But they never had enough evidence to charge them.

Padilla said Shermantine calls the well "Herzog's boneyard," and pins all the bodies that will be found there on Herzog. That's nothing new. Beyond steadfastly refusing to disclose the location of bodies, the childhood friends have also maintained that the other single handedly did all the killing.

Herzog hanged himself on Jan. 16 outside the Susanville trailer he was paroled to after an appeals court tossed out his confession as illegally coerced. He committed suicide hours after Padilla told him Shermantine was prepared to tell authorities about the missing.

"I could hear him catch his breath when I mentioned the well," Padilla said of his conversation with Herzog on Jan. 16. "He thanked me, and didn't say anything more, but I could hear him catch his breath."

On Thursday, at a site in Calaveras County near property Shermantine's parents once owned, searchers found a skull identified as Cyndi Vanderheiden, who disappeared in 1998. The next day, about a ¼ mile away, searchers found a blanket containing a partial skull and other remains believed to belong to Wheeler.

Shermantine was convicted of both women's murders in 2001. He was arrested in 1999 after his car was re-possessed and investigators found Vanderheiden's blood in the trunk. Using a new collection technique not available in 1985, they also found Wheeler's DNA in a remote Calaveras County cabin owned by Shermantine. The cabin was near where Wheeler's body was found.

Shermantine was also convicted of robbing and killing two drifters as they sat in a car in a rural area about two miles west of Stockton. Tire tracks left at the scene matched those of a red pickup Shermantine drove at the time.

During his trial, which opened in 2000 and was moved to Santa Clara because of publicity in the Central Valley, prosecutor Thomas Testa told the jury that Shermantine was suspected of killing 20 people. Testa told the jury that Shermantine boasted publicly — and threateningly __ on several occasions about his ability to make people disappear.

"There are no fingerprints, no eyewitnesses, no smoking gun," Testa said in his opening statement. "Wes told several individuals that he had hunted the ultimate kill: humans."

John Vanderheiden, Cyndi's father, owns a Clement bar the deadly duo frequented. Vanderheiden said Shermantine boasted loudly on several occasions that he was a killer.

Vanderheiden said he chalked it up to drunken nonsense — until his daughter disappeared.

Shermantine was convicted of four murders and sentenced to death.

Another Santa Clara jury rejected Testa's plea that Herzog also receive the death penalty after he was initially charged with five first-degree murders.

Instead, Herzog was convicted of first-degree murders for his involvement in the deaths of the drifters and Vanderheiden. The jury rejected the same charges for the murder of Henry Howell, who investigators suspect Shermantine killed in September of 1984 on a lonely stretch of highway in Hope Valley, between Lake Tahoe to Stockton. Howell is believed to be the duo's first victim.

Herzog was sentenced to 78 years in prison, but that sentenced was reduced to 14 years after an appeals court tossed out his confession as coerced and prosecutors reluctantly offered him a deal to plead guilty to a voluntary manslaughter charge connected to Vanderheiden's death and three accessory to murder charges connected to the killings of the drifters and Howell. He was paroled in 2010.