Loren Joseph Herzog and the Speed Freak Killers
Background
Loren Joseph Herzog was born on December 8, 1965, in California and grew up in the rural community of Linden in San Joaquin County. His longtime friend Wesley Howard Shermantine Jr. lived nearby. The two men attended school together and became familiar with the isolated roads, farms, waterways, foothills, wells, and abandoned properties surrounding Linden and Stockton.
Herzog and Shermantine became known as the “Speed Freak Killers,” a nickname connected to their frequent use of methamphetamine. Investigators suspected that the pair committed violent crimes while using drugs and traveling through remote areas of Northern California. Their alleged offenses included robbery, kidnapping, sexual assault, murder, and the concealment of human remains.
The exact number of their victims has never been established. Some victims were included in criminal trials, while others were linked to the men through physical evidence, witness statements, recovered remains, or later claims made by Shermantine. It is important to distinguish between victims legally connected to Herzog, victims proven against Shermantine alone, and people who remain suspected victims.
Victims Established in Herzog’s Final Criminal Case
- Henry Lee Howell, age 41 — killed September 1, 1984 — Highway 88 near Hope Valley, California: Howell was found dead beside or inside his vehicle along a remote mountain highway. He had been shot and had suffered severe injuries to his head and mouth. Herzog told investigators that he and Shermantine encountered Howell while traveling through the area and that Shermantine killed and robbed him. Herzog eventually pleaded guilty to being an accessory after Howell’s murder.
- Howard Michael King III, age 35 — killed November 27, 1984 — Roberts Island, southwest of Stockton, California: King was sitting in the driver’s seat of a Pontiac parked on an isolated road when he and his passenger were confronted. King was shot and killed. Tire impressions found near the crime scene were later associated with Shermantine’s red pickup truck. Herzog was originally convicted of King’s murder, but that conviction was overturned. He later pleaded guilty to acting as an accessory after the killing.
- Paul Raymond Cavanaugh, age 31 — killed November 27, 1984 — Roberts Island, southwest of Stockton, California: Cavanaugh was the passenger in the vehicle occupied by Howard King. Herzog told detectives that Cavanaugh was removed from the car and shot at close range. Herzog’s original murder conviction was overturned with his other convictions. He subsequently pleaded guilty to being an accessory after Cavanaugh’s murder.
- Cynthia Ann “Cyndi” Vanderheiden, age 25 — disappeared and presumed killed November 14, 1998 — last seen in the Linden and Clements area of California: Vanderheiden disappeared after spending part of the evening at the Linden Inn, a bar owned by her family. She was last seen in the company of Herzog and Shermantine. Her blood was later discovered inside Shermantine’s vehicle. Herzog was originally convicted of her murder, but the conviction was overturned on appeal. He later pleaded guilty to voluntary manslaughter and to furnishing her with methamphetamine. In February 2012, part of her skull was recovered from a ravine near San Andreas in Calaveras County.
Chevelle “Chevy” Wheeler
- Chevelle Yvonne Wheeler, age 16 — disappeared October 16, 1985 — Stockton, California: Wheeler left Franklin High School after telling a friend that she was going with a man named Wes to the Valley Springs or San Andreas area. She was seen entering a red pickup truck associated with Shermantine. Before leaving, she reportedly told her friend to notify her father if she failed to return.
Evidence later connected Wheeler to a cabin used by Shermantine near San Andreas. Shermantine was convicted of kidnapping and murdering her. Herzog was not convicted of Wheeler’s death, so she should be described as a confirmed victim of Shermantine and a victim connected to the broader Speed Freak Killers case, rather than as a legally confirmed victim of Herzog.
In 2012, Shermantine directed investigators to a location where Wheeler’s remains were recovered. The discovery confirmed that she had been murdered after disappearing in 1985.
Roberta Ray “Robin” Jones Armtrout
- Roberta Ray “Robin” Jones Armtrout, age 24 — killed September 8, 1985 — Potter Creek area near Linden, California: Armtrout was last seen entering a red pickup truck with Herzog and Shermantine. Her unclothed body was later discovered near Potter Creek by a hunter. She had been stabbed repeatedly.
Herzog was prosecuted for Armtrout’s murder but was acquitted. Although the circumstances placed her in the company of Herzog and Shermantine shortly before her death, the jury did not find Herzog guilty beyond a reasonable doubt. She should therefore be identified as a victim associated with the pair and with Herzog’s trial, not as a murder for which Herzog was convicted.
Kimberly Ann Billy and JoAnn Hobson
- Kimberly Ann Billy, age 19 — disappeared December 11, 1984 — Stockton, California: Billy vanished from Stockton and remained missing for more than twenty-seven years. Her precise date and location of death have not been publicly established. In February 2012, investigators recovered her remains from an abandoned well on Flood Road near Linden after Shermantine supplied information about the site.
- JoAnn Hobson, age 16 — disappeared August 29, 1985 — Stockton, California: Hobson disappeared from Stockton and was not seen alive again. Her exact date of death is unknown. Her remains were recovered in 2012 from the same abandoned Linden-area well that contained Kimberly Billy’s remains and the remains of at least one additional unidentified person.
The recovery site strongly connected Billy and Hobson to the Speed Freak Killers investigation. Authorities described the well as a disposal location used by the killers. Nevertheless, neither Herzog nor Shermantine was convicted of murdering Billy or Hobson, and the publicly known evidence does not establish which man killed them or whether both participated. Their disappearance dates should not automatically be presented as verified dates of death.
Tracy Diane Melton
- Tracy Diane Melton, age 32 — disappeared May 6, 1998 — Stockton, California: Melton vanished from Stockton several months before Cyndi Vanderheiden disappeared. A fragment of Melton’s bone was found near Linden in 2003 and was identified through DNA testing in 2011. Her family was informed of the identification in 2012.
Melton is deceased, but the precise date, location, and circumstances of her death remain undetermined. Her disappearance date of May 6, 1998, should not be stated as a confirmed date of death. Investigators considered Herzog and Shermantine possible suspects because of the location of her remains and the timing of her disappearance, but no one was convicted of killing her.
Phillip Cabot Lloyd Martin
- Phillip Cabot Lloyd Martin, age 47 — last seen September 30, 1993 — north Stockton, California: Martin was a father who failed to pick up his daughters from school and was never heard from again. His daughter reported that he had worked with Shermantine and may have used drugs with Shermantine and Herzog.
Martin remains missing, and no body has been identified as his. Shermantine has been considered a possible suspect in his disappearance, but Martin has not been legally declared a confirmed victim of either man. September 30, 1993, is his last-known-alive date rather than a verified date of death.
Investigation and Arrest
The investigation that led to the arrests of Herzog and Shermantine intensified after Cyndi Vanderheiden disappeared in November 1998. When Shermantine’s vehicle was repossessed and searched, investigators discovered Vanderheiden’s blood inside it. Detectives then focused on Herzog as a possible participant and as someone who might provide information about Shermantine.
Herzog underwent lengthy interrogations in March 1999. During questioning, he described several killings in detail while repeatedly claiming that Shermantine had committed the actual violence. Herzog attempted to portray himself as a frightened witness who had been unable to stop his friend. Investigators believed that his detailed knowledge demonstrated that he was present during several crimes and had assisted Shermantine.
Herzog and Shermantine were arrested on March 17, 1999. They were tried separately. Shermantine was convicted of murdering Cyndi Vanderheiden, Howard King, Paul Cavanaugh, and Chevelle Wheeler. He was sentenced to death.
Herzog’s Trial and Overturned Convictions
In 2001, Herzog was convicted of murdering Cyndi Vanderheiden, Howard King, and Paul Cavanaugh. He was also convicted as an accessory in Henry Howell’s death. He was acquitted of murdering Robin Armtrout. Herzog received a prison sentence of 78 years.
In 2004, a California appellate court overturned Herzog’s major convictions. The court determined that detectives had used improper psychological pressure during his interrogations and that important portions of his statements had not been voluntary. Because the prosecution had relied heavily on those statements, the convictions could not remain in effect.
Rather than conduct another complete trial, prosecutors reached a plea agreement with Herzog. He pleaded guilty to voluntary manslaughter and furnishing methamphetamine in connection with Vanderheiden’s death. He also pleaded guilty to acting as an accessory after the murders of Howell, King, and Cavanaugh. Herzog was sentenced to 14 years, with credit for the years he had already served.
Release and Death
Herzog was released on parole in September 2010. Public opposition made it difficult for authorities to find a community willing to house him. He was eventually placed in a trailer on state property near High Desert State Prison in Susanville, California. He remained under strict parole supervision and wore an electronic monitoring device.
On January 16, 2012, Herzog was found dead inside the trailer. His death was ruled a suicide by hanging. He died shortly after learning that Shermantine was providing maps and information about locations where additional victims had been buried or discarded.
Recovery of Additional Remains
Information supplied by Shermantine in 2012 led investigators to a ravine near San Andreas and to an abandoned well near Linden. Part of Cyndi Vanderheiden’s skull and the remains of Chevelle Wheeler were recovered near San Andreas. The Linden well contained more than one thousand bone fragments belonging to multiple people.
Kimberly Billy and JoAnn Hobson were identified among the people whose remains were recovered from the well. Investigators also found remains belonging to at least one unidentified person and an unidentified fetus. The discoveries demonstrated that the Speed Freak Killers investigation involved more victims than the four murders established in the original trials.
Confirmed and Suspected Victim Totals
There is no single reliable total for Loren Herzog’s victims. Four deaths were directly addressed in his final plea agreement: Vanderheiden through a voluntary-manslaughter plea, and Howell, King, and Cavanaugh through accessory pleas. Wheeler was a proven victim of Shermantine. Armtrout was connected to the men, but Herzog was acquitted of her murder. Billy, Hobson, Melton, and Martin belong in discussions of suspected or associated victims, but they should not all be described as legally confirmed victims of Herzog.
Shermantine later claimed that he and Herzog had killed many more people, sometimes suggesting totals reaching several dozen. These statements have never been fully verified. The number of victims may be greater than the number established in court, but the available evidence does not justify presenting every missing person investigated in connection with the pair as a confirmed murder victim.
