David Joseph Carpenter (born May 6, 1930), also called the Trailside Killer, is an American serial killer and sex offender who raped and murdered various victims in the San Francisco Bay Area between 1979 and 1981. He was sentenced to death for seven murders and is believed to be responsible for several more.
Carpenter began committing sexual assaults at age 15 and was admitted to a mental hospital at age 17. He committed all of his murders while on parole for rape and kidnapping convictions. Active primarily in Marin County and Santa Cruz County, Carpenter would hide along tree lines on secluded trails and wait for his target to approach and then would restrain, rape, and sometimes torture them before killing them. A .38 caliber handgun was his preferred weapon, which was used in all but one of the killings. According to pathologists, Carpenter would get so much enjoyment from tormenting his victims that he would lose his stutter.
Both of Carpenter's trials had to be moved to Southern California due to extensive publicity. In 1984, he was tried and convicted in Los Angeles County of two murders and one attempted murder, for which he was sentenced to death. Four years later, he was tried and convicted in San Diego County of five additional murders and given another death sentence. He is currently incarcerated at California Health Care Facility in Stockton, California. Carpenter is currently the oldest death row inmate in the United States.
Early life
David Joseph Carpenter was born in San Francisco on May 6, 1930. In his youth, he suffered physical abuse by his alcoholic father Elwood and domineering mother Frances, mostly concerning his persistent bed-wetting and cruelty to animals. Frances barred young Carpenter from playing outside with neighborhood kids and forced him to learn to play the violin and take ballet lessons.
Carpenter attended Glen Park Elementary School, where he was bullied for having a stutter. His teachers recommended him to enroll in speech therapy but Frances resisted all efforts. After he was accused of biting a childhood friend, Carpenter was absent from school for several days and returned with bruises on his arms and legs. Around the time he reached adolescence, he sparked a fierce temper that psychologists would claim developed into sexual rage. He attended Balboa High School until he was thrown out in his sophomore year for dragging a female student down the hall after an argument.
Carpenter has acknowledged he molested several children in his adolescence, including two of his cousins, beginning when he was 15 years old. At age 17, he was arrested for the first time on allegations he sexually assaulted a 3-year-old girl. He was placed in custody of the California Youth Authority before spending several years at Napa State Hospital. When referring to the escalation of Carpenter's crimes, his mother was quoted saying to a probation officer, "As soon as he was able to walk, he was getting into trouble". That same probation officer described him as "quite a liar".Final prosecution witness testifies in Trailside penalty trial. The Hanford Sentinel. United Press International. September 20, 1984. Retrieved August 3, 2025. In 1950, Carpenter was arrested for the rape of a 17-year-old girl, and after pleading not guilty he was acquitted at trial.
In the mid-1950s, Carpenter was employed as a purser on SS Fleetwood. In 1955, he married Ellen Cooke, with whom he had three children before their divorce in 1961. Carpenter later remarked to a psychiatrist that his first marriage was unsatisfactory because Cooke "was not interested in anything but local neighborhood gossip". Cooke would say that Carpenter was domineering, strong-willed, and charming, and said she knew nothing of his prior run-ins with law enforcement.Killer's ex-wife testifies in trial. Camarillo Star. Associated Press. September 20, 1984. Retrieved August 12, 2025.
First offences Carpenter later gained employment at a San Francisco post office where he met 32-year-old Lois DeAndrade, the future mother of television personality Lisa Rinna. On July 11, 1960, Carpenter, armed with a knife and hammer, was prowling through San Francisco when he approached his friend DeAndrade. He convinced her to get in his car and drove her to the Presidio where he attacked her; slashed her hands with the knife; when she fell to the ground, he beat her on the head with the hammer. The attack was interrupted by Jewell Hicks, a military officer, who shot and wounded Carpenter. Once in recovery, DeAndrade claimed that, despite Carpenter's apparent stutter, she didn't recall him stuttering at all during the attack. After his arrest, he was booked for assault with a deadly weapon and pleaded guilty, receiving a 14-year federal prison sentence. Carpenter claimed his "trigger" to commit the attack was the 1960 film Psycho. He earned a high school diploma during his incarceration and was released in 1969, subsequently marrying his second wife, Helen.
1970 From January to February 1970, Carpenter went on a crime spree in the Bay Area. The first of these cases occurred after he rear-ended a vehicle being driven by a young woman, and after a heated exchange he shoved her to the ground and raped her before stabbing her with a spatula. He was armed with a hunting knife during the second attack, which was against a 19-year-old girl in Boulder Creek. On February 3, he forced his way into the home of 45-year-old Lucille Davis in Modesto, where he bound her wrists and demanded her car keys, and he subsequently stole her vehicle and drove to Angels Camp. There, he confronted a 21-year-old mother and forced her to drive him to Oakdale while her 16-month-old son sat in the back of the vehicle. When they arrived, Carpenter forced both out and drove off.Calaveras Has Suspect In Abduction, Terror. The Sacramento Bee. February 4, 1970. Retrieved August 3, 2025. After he was detained on February 4, investigator James Marston obtained permission from Carpenter's wife to search their vehicle, which was found to have contained the knife used in the second attack.Trailside Killer prosecution rests. The Napa Valley Register. United Press International. August 22, 1984. Retrieved August 1, 2025.
Around the time of his arrest, the Zodiac Killer was active in the San Francisco Bay Area, which drew high media attention and search efforts. In an effort to gain some sort of attention to himself, Carpenter began to refer to himself as "Zodiac" to other inmates. Authorities were alerted and investigated him, but since he had been imprisoned during the time three of the murders occurred, he was cleared. On April 26, Carpenter and five other inmates being held at the Calaveras County jail cut their way through cell bars and escaped. He was captured two weeks later and sentenced to five-years-to-life imprisonment for auto theft and escape charges, and five-to-twenty-five years on kidnapping charges.
Incarceration
During a presentencing hearing, it was estimated that Carpenter had an intelligence quotient (IQ) of 125.Haines, Max (October 16, 1993). TRAIL OF DEATH. North Bay Nugget. Retrieved August 5, 2025. He initially served his sentence at Folsom State Prison until being transferred to San Quentin State Prison in 1972, later returning to Folsom before being transferred to California Medical Facility. A psychiatrist's report identified him with having antisocial personality disorder (ASPD), which the United States Parole Commission defined as someone who is manipulative and a pathological liar.'Trailside Killer' trial due to begin. Santa Barbara News-Press. Associated Press. October 9, 1983. Retrieved August 5, 2025. Despite many warnings, Carpenter was paroled for the California convictions in February 1977 but was immediately turned over to federal custody for other convictions. Around 1978, Carpenter befriended fellow inmate Shane Mitchell Williams, who was serving time for several bank robberies committed in Los Angeles.
Carpenter was granted full release on May 2, 1979, and transferred to a halfway house for 60 days and afterwards moved in with his parents in San Francisco's Glen Park neighborhood. Under his parole conditions, he would remain on supervision until October 28, 1982, and would have to report monthly to his parole officer in San Francisco. In October 1979, he began attending a vocational school in Hayward to learn offset printing, and after several months of training he was hired to lecture the course.
After Williams' release, he and his wife, Karen Kilroy, made trips to San Francisco to visit Carpenter, and together the trio attended punk clubs along Broadway.Alleged trailside killer's pals held in bank robbery. The San Francisco Examiner. June 14, 1981. Retrieved August 3, 2025. When they confided in Carpenter about wanting to resume committing robberies, Carpenter instructed the couple that using a gun would make getting away with their crimes easier.Todd, John (September 22, 1985). Trailside Killer' gave lessons on robbery, witness says. The San Francisco Examiner. Retrieved August 1, 2025. Thereafter, the couple went on a crime spree with a .38 caliber revolver loaned to them by Carpenter, which had previously been used in several of the murders. Williams and Kilroy committed robberies in San Francisco, Los Angeles, and Phoenix, Arizona. On June 1, 1981, after Carpenter's arrest, Williams and Kilroy were arrested for a botched robbery on Ventura Boulevard and subsequently were connected to their previous crimes.
Murders Carpenter is believed to have begun killing in the summer of 1979. His modus operandi was to hide in tree lines along hiking trails and then confront his targets once they approached. Carpenter was convicted of seven murders which occurred between October 1980 and May 1981 in Marin County and Santa Cruz County. He was also linked via DNA—albeit not charged with—an October 1979 murder in San Francisco. Two other murders, lacking physical evidence, are also believed to have been committed by him, along with the suspected homicide of a teenage girl in Daly City. He originally used a knife in his attacks until he duped a female friend into buying him a .38 caliber revolver in 1980. All of Carpenter's suspected victims were aged between 18 and 44, the majority of which were in their early twenties.
Before Carpenter's identification, the murderer was known as the "Mount Tam Killer" by Marin County investigators as most of the killings there occurred within range of Mount Tamalpais. Early on, investigators incorrectly believed the killer was in his 20s or 30s, while Carpenter was 50. After his murders stretched into Santa Cruz County in 1981, he was redubbed the "Trailside Killer". A more accurate depiction of the killer as a balding man in his 50s helped police arrest Carpenter.Survivor says woman defied killer who threatened rape, then shot her. The San Bernardino Sun. Associated Press. May 20, 1981. Retrieved August 1, 2025.
1979