Wesley Howard Shermantine and the Speed Freak Killers
Background
Wesley Howard Shermantine Jr. was born on February 24, 1966, and grew up in Linden, a small agricultural community east of Stockton in San Joaquin County, California. He became closely associated with childhood friend Loren Joseph Herzog. The two men later became known as the “Speed Freak Killers,” a name referring to their heavy use of methamphetamine during the years in which their crimes occurred.
Shermantine and Herzog knew the rural landscape surrounding Linden, Stockton, San Andreas and other parts of Northern California exceptionally well. They hunted, fished and traveled through isolated farmland, mountain roads, abandoned properties and former mining areas. Investigators later believed that this familiarity allowed them to select secluded places where victims could be attacked and where bodies or evidence could be concealed.
The full extent of Shermantine’s crimes remains unknown. He was convicted of four murders, but investigators have examined his possible connection to numerous additional disappearances and killings. Shermantine has made shifting and sometimes sensational claims about the number of victims, at one point suggesting that dozens of people had been killed. Many of those claims have never been independently verified, and authorities have cautioned that the actual victim count cannot be established from Shermantine’s statements alone.
The Murders of Howard King and Paul Cavanaugh
On November 27, 1984, Howard Michael King III and Paul Raymond Cavanaugh were together in a Pontiac parked on Roberts Island, southwest of Stockton. Both men were shot at close range. Their bodies were discovered inside or near the vehicle in the isolated rural area.
Investigators documented tire impressions and other evidence surrounding the crime scene. The prosecution later connected the killings to Shermantine and Herzog. Testimony attributed to Herzog described the two men approaching the parked car with shotguns before King and Cavanaugh were killed. Shermantine was ultimately convicted of murdering both men during a robbery.
- Howard Michael King III: Age 35. Killed on November 27, 1984, on Roberts Island in San Joaquin County, California. He was found shot in or near a parked Pontiac.
- Paul Raymond Cavanaugh: Age 31. Killed on November 27, 1984, on Roberts Island in San Joaquin County, California. He was also found shot at the rural crime scene.
The Disappearance and Murder of Chevelle Wheeler
Chevelle Yvonne “Chevy” Wheeler was a 16-year-old student at Franklin High School in Stockton. On October 16, 1985, she left school after telling a friend that she planned to travel with a man named “Wes” to a cabin near Valley Springs or San Andreas. She reportedly appeared uneasy about the trip and asked the friend to notify her father if she did not return.
Chevelle was last seen getting into a red pickup truck. Shermantine, who knew members of her family, owned a truck matching that description and had access to a family cabin in Calaveras County. Investigators searched the cabin and collected biological evidence. Advances in DNA testing later allowed authorities to associate blood and hair evidence from the property with Chevelle.
Her body has never been recovered. Nevertheless, prosecutors argued that the physical evidence, Shermantine’s connection to the cabin and the circumstances of Chevelle’s disappearance proved that he had killed her. A jury agreed and convicted him of her murder.
- Chevelle Yvonne “Chevy” Wheeler: Age 16. Last seen alive on October 16, 1985, after leaving Franklin High School in Stockton, California. She was believed to have been taken to Shermantine’s family cabin in the San Andreas area of Calaveras County. Her exact time and place of death have never been established because her remains have not been found.
The Disappearance and Murder of Cyndi Vanderheiden
Cynthia Ann “Cyndi” Vanderheiden was 25 years old and lived in Clements, California, a community near Linden. She disappeared during the night of November 14, 1998. Before vanishing, she had been socializing at a bar in Linden where Shermantine and Herzog were also present.
Investigators learned that Herzog had driven Cyndi home but that she apparently left again afterward. Suspicion focused on Herzog and Shermantine as detectives reconstructed the final hours in which she had been seen alive. Her vehicle was located, but Cyndi could not be found. Both men were arrested in March 1999 as the investigation expanded to include several older killings and disappearances.
Shermantine was convicted of Cyndi’s murder even though her body had not yet been located. More than a decade later, he provided information describing a burial site near property once owned by his family in Calaveras County. In February 2012, investigators searched a ravine in the San Andreas area and recovered human remains. Dental records confirmed that a skull found at the location belonged to Cyndi Vanderheiden.
- Cynthia Ann “Cyndi” Vanderheiden: Age 25. Last seen alive during the night of November 14, 1998, in the Linden and Clements area of San Joaquin County, California. Her remains were recovered in February 2012 from a ravine near San Andreas in Calaveras County. Her precise date of death could not be medically established, but investigators concluded that she was killed shortly after she disappeared.
Roberta “Robin” Armtrout
Roberta Ray “Robin” Jones Armtrout was a 24-year-old woman whose killing became an important part of the broader investigation into Shermantine and Herzog. On September 8, 1985, she was seen leaving with the two men in a red pickup truck after meeting them in Stockton. Her body was later discovered near Potter Creek outside Linden.
Armtrout had been stabbed repeatedly, and investigators believed she had been sexually assaulted before her death. Herzog gave detectives an account implicating Shermantine, but the case did not produce a murder conviction against Shermantine. Herzog was prosecuted for Armtrout’s killing and was acquitted of that count. Although the circumstances have long caused investigators to associate the case with the pair, responsibility for Armtrout’s death was not conclusively established by a final conviction.
- Roberta Ray “Robin” Jones Armtrout: Age 24. Killed on or about September 8, 1985, after leaving Stockton with Shermantine and Herzog. Her body was found near Potter Creek outside Linden, California. Shermantine was suspected but was not convicted of her murder.
Henry Lee Howell
Henry Lee Howell, a 41-year-old man from Santa Clara, was found shot beside Highway 88 in the Hope Valley area of Alpine County. He had stopped along the remote mountain highway on September 1, 1984. Herzog later gave detectives a statement alleging that Shermantine approached Howell and shot him with a shotgun.
Shermantine was not convicted of Howell’s murder. Herzog was charged in connection with the killing but was found guilty of being an accessory rather than the person who committed the murder. The account implicating Shermantine remains one of the allegations used to demonstrate the possible breadth of the pair’s criminal activity.
- Henry Lee Howell: Age 41. Killed on September 1, 1984, along Highway 88 near Hope Valley in Alpine County, California. He died from a shotgun wound. Shermantine was accused of being the shooter but was not convicted of Howell’s murder.
Kimberly Billy and JoAnn Hobson
In February 2012, investigators acting on information supplied by Shermantine searched an abandoned well on Flood Road near Linden. Hundreds of human bone fragments, clothing and personal items were recovered. DNA testing identified remains belonging to two missing teenagers, Kimberly Ann Billy and JoAnn Hobson.
Kimberly Billy was 19 years old when she disappeared from Stockton on December 11, 1984. JoAnn Hobson was 16 when she disappeared from Stockton on August 29, 1985. Their remains had been mixed among numerous fragments inside the well, making it difficult to determine the exact circumstances or dates of their deaths.
The discovery established that both young women had been killed and placed in a burial site known to Shermantine. However, he has not been convicted of either murder. The specific role played by Shermantine, Herzog or another person in their deaths has not been conclusively determined in court.
- Kimberly Ann Billy: Age 19. Disappeared from Stockton, California, on December 11, 1984. Her remains were identified in 2012 after being recovered from an abandoned well near Linden. Her exact date and location of death remain undetermined.
- JoAnn Hobson: Age 16. Disappeared from Stockton, California, on August 29, 1985. Her remains were identified in 2012 among bones recovered from the Linden well. Her exact date and location of death remain undetermined.
Additional Unidentified Remains
The excavation of the Linden well produced more than one thousand human bone fragments. Not all of those remains could be identified, and investigators determined that more than two individuals had likely been placed there. The recovery process was complicated by the depth and condition of the well, the mixing of remains and earlier excavation methods that damaged or scattered evidence.
Authorities also searched areas near former Shermantine family property in Calaveras County. In addition to Cyndi Vanderheiden’s remains, investigators recovered remains believed to belong to at least one unidentified person. Other wells and rural locations identified by Shermantine were searched without producing confirmed victims.
Because several recovered remains remain unidentified, the possibility that additional victims are connected to Shermantine and Herzog has never been eliminated. Families of missing people from the Stockton, Linden and San Joaquin County areas have continued to seek DNA comparisons and renewed examinations of evidence.
Arrest and Investigation
Shermantine and Herzog were arrested in March 1999 after detectives questioned Herzog at length about Cyndi Vanderheiden’s disappearance and several unsolved murders. Herzog provided statements implicating Shermantine in multiple crimes. Shermantine denied responsibility and accused Herzog of being the actual killer.
The investigation combined old crime-scene evidence, witness testimony, forensic testing and the statements the two men made about each other. DNA evidence from the Shermantine cabin became particularly important in the Chevelle Wheeler prosecution. Evidence from the Roberts Island shooting and testimony concerning Cyndi Vanderheiden’s disappearance also contributed to the case.
During Shermantine’s trial, jurors heard testimony describing a long history of violence, threats and sexual assaults against women. Several witnesses described being attacked, terrorized or abused by him. The prosecution portrayed Shermantine as a predatory and controlling man whose violent behavior extended beyond the four murders charged in the case.
Conviction and Death Sentence
In 2001, Shermantine was convicted of four counts of first-degree murder for the deaths of Howard King, Paul Cavanaugh, Chevelle Wheeler and Cyndi Vanderheiden. The jury also found special circumstances, including multiple murder and robbery-related allegations, making him eligible for the death penalty.
Shermantine received a death sentence. His conviction established his legal responsibility for four murders committed between 1984 and 1998. The cases of Wheeler and Vanderheiden demonstrated that a murder conviction could be secured through circumstantial and forensic evidence even before the victim’s remains were recovered.
Herzog was separately convicted of murdering King, Cavanaugh and Vanderheiden, along with lesser offenses connected to other crimes. His murder convictions were later overturned after an appellate court ruled that his confession had been improperly obtained. He eventually pleaded guilty to reduced charges and was released on parole in 2010. Herzog died by suicide on January 16, 2012, shortly before searches based on Shermantine’s maps began producing human remains.
Shermantine’s Maps and the Search for Victims
While imprisoned, Shermantine began offering information about burial locations. His cooperation was inconsistent and was often tied to demands for money. Bounty hunter Leonard Padilla arranged payments in exchange for maps and descriptions of places where Shermantine claimed victims had been buried.
The information led investigators to the Flood Road well near Linden and to locations in Calaveras County. The resulting discoveries included the remains of Cyndi Vanderheiden, Kimberly Billy and JoAnn Hobson. These findings demonstrated that at least some of Shermantine’s information was accurate.
Other claims proved unreliable or led to searches that uncovered nothing. Shermantine alleged that he knew the locations of many more victims, but he frequently refused to provide complete information or changed his account. Authorities have therefore treated his unverified claims cautiously.
Possible and Suspected Victims
Shermantine and Herzog have been investigated in connection with additional missing people from Northern California. In many of these cases, the evidence is limited to geographic proximity, personal acquaintance, statements made by Shermantine or Herzog, or the possibility that the missing person encountered one of the men.
Those cases should not be described as confirmed murders by Shermantine. Some individuals disappeared before the period covered by his convictions, and others may have no connection to him. Investigators have continued comparing unidentified remains and preserved evidence with records from unresolved missing-person cases.
- Ruth Ann Leamon: Age 16. Disappeared from Modesto, California, on August 19, 1982. She reportedly had some prior contact with Herzog, but no conclusive evidence has established that Shermantine or Herzog caused her disappearance.
- Susan Robin Bender: Age 15. Disappeared from Modesto, California, on April 25, 1986. Shermantine and Herzog have been examined as possible suspects, but neither man was charged in her case.
- Sylvia Lourdes Standly: Age 30. Disappeared from Modesto, California, on June 4, 1986. Her case has been discussed in connection with the wider investigation, but no confirmed link to Shermantine has been established.
Uncertain Victim Count
Shermantine was legally convicted of four murders. Evidence recovered after his trial connected burial sites known to him with additional victims, but those discoveries did not result in further murder convictions. Estimates claiming that Shermantine and Herzog killed 19, 25 or more than 70 people are based on investigative suspicions, unidentified remains and Shermantine’s own unverified statements.
The confirmed facts reveal a series of killings spanning at least fourteen years. Victims included two men attacked in a parked car, two teenage girls who disappeared after encountering Shermantine or visiting a property associated with him, and a young woman whose remains were hidden in a remote ravine. Other women and girls were placed in an abandoned well that remained concealed for decades.
Legacy of the Case
The Shermantine investigation remains one of the most disturbing serial-murder cases in California’s Central Valley. It exposed how killers familiar with a rural region could use wells, ravines and isolated properties to hide victims for many years. It also demonstrated the importance of preserving biological evidence, as improved DNA testing helped solve the murder of Chevelle Wheeler long after her disappearance.
For the families of identified and possible victims, the later discoveries brought a mixture of answers and renewed grief. Some families were finally able to learn where their loved ones had been placed, while others remained uncertain whether unidentified remains belonged to missing relatives. Disputes over excavation procedures and the handling of recovered bones added further controversy to an already painful investigation.
Wesley Howard Shermantine remains convicted of the murders of Howard King, Paul Cavanaugh, Chevelle Wheeler and Cyndi Vanderheiden. The discoveries made from his maps strongly suggest that the four convictions represent only part of the violence surrounding Shermantine and Herzog. However, the identities of all the people buried in the locations connected to them, and the true number of their victims, remain unresolved.
