Wesley Shermantine, one of the two methamphetamine-fueled serial killers known as the Speed Freak Killers, died Thursday at age 60 inside California State Prison, Folsom. The condemned inmate was pronounced dead at 6 p.m. in the facility's central health building, according to official records from the California Department of Corrections and Rehabilitation.
Shermantine was a condemned inmate in California's prison system. The Sacramento Bee reports the Sacramento County Coroner's Office will determine his exact cause of death, and that Shermantine was one of 563 condemned inmates remaining in the California state prison system. His presence at CSP-Sacramento rather than San Quentin, where he had been housed as recently as 2012, traces back to California's Condemned Inmate Transfer Program, which by mid-2024 had finished moving death row inmates out of San Quentin's segregated units and into general population facilities statewide under Proposition 66, according to the California Department of Corrections and Rehabilitation.
A Killing Spree Rooted in San Joaquin County
Shermantine and his accomplice, Loren Herzog, operated in San Joaquin County during a methamphetamine-fueled killing spree that earned them the nickname the Speed Freak Killers, the Sacramento Bee reports. The pair were ultimately convicted of murdering four people and sentenced to death, though investigators and victim families have long suspected the two of killing more than 70 people across the region.
Shermantine and Herzog were arrested in March 1999, and Chevelle Wheeler had disappeared in 1985, according to a report referenced by Wikipedia. Wheeler reportedly disappeared after saying she was going with Shermantine to a cabin.
A Legal Loophole Freed One Killer, Then Cost Him His Life
Herzog's 2001 murder convictions did not hold. The California Court of Appeal overturned them in 2004 after judges ruled his confessions had been illegally coerced by police, a decision that let him negotiate a plea to voluntary manslaughter and secure parole in 2010, as detailed by SFGATE. Herzog had originally received a 78-year sentence before that ruling.
Herzog's freedom did not last. In January 2012, he died by suicide outside High Desert State Prison in Susanville, where he had been living in a trailer while on parole, hours after receiving a phone call from bounty hunter Leonard Padilla warning him that Shermantine was revealing their victim burial sites to law enforcement, per The Guardian. He was 46.
Bones, Bounty, and a Well in Linden
Padilla had persuaded Shermantine to turn over maps showing where victims were buried in exchange for $30,000. Shermantine had refused to disclose burial sites for more than a decade before that arrangement.
Guided by those maps, excavation of an abandoned cattle ranch well in Linden yielded more than 1,000 human bone fragments along with clothing, purses, and jewelry buried deep in the pit, the Guardian's reporting shows. The Linden site sat roughly 60 miles east of San Francisco in rural San Joaquin County. In August 2012, corrections officials escorted Shermantine under heavy guard to additional suspected burial sites as he helped investigators search for more remains, per the Sacramento Bee.
By March 2012, forensic scientists using DNA and dental records had identified remains from the Linden well as belonging to 19-year-old Kimberly Billy and 16-year-old JoAnn Hobson, both missing from Stockton since 1984 and 1985 respectively, according to the Los Angeles Times. Separately, the Sacramento Bee reports the San Joaquin County Sheriff's Office used DNA testing to identify Cyndi Vanderheiden and Chevy Wheeler, whose remains were found days apart in 2012 in Calaveras County, with Shermantine's maps having led investigators to hundreds of bone fragments there.
A Family's Lawsuit Over How Remains Were Recovered
The recovery effort itself became a source of lasting grief. JoAnn Hobson's mother filed a civil rights lawsuit against San Joaquin County in 2013, alleging investigators desecrated her daughter's remains by using a heavy backhoe excavator rather than hand shovels, according to Courthouse News Service. Law enforcement had allegedly promised the family they would switch to hand shovels once human remains were found. A federal judge denied the county summary judgment in that case in October 2017.
Shermantine's Death Fits a Broader Shift on Death Row
Shermantine's death comes as California's death row population has declined. The state's condemned population was 589 as of April 10, 2025. The Death Penalty Information Center reports that California has not carried out an execution since 2006.
With Shermantine's death, neither of the Speed Freak Killers' two convicted killers remains alive. Investigators and victim families had long suspected the true toll of the pair's killings stretched far beyond the four murders for which they were convicted, and Shermantine's cooperation in 2012 remained the primary route to locating additional remains buried across the Central Valley. Shermantine had been a source of information about burial locations.
