David Joseph Carpenter: The Trailside Killer
David Joseph Carpenter, born May 6, 1930, in San Francisco, California, became one of Northern California's most notorious serial killers. Known as the "Trailside Killer," Carpenter preyed on people using hiking trails and wooded recreation areas around the San Francisco Bay Area. His crimes were concentrated in Marin and Santa Cruz counties, where the peaceful isolation of places such as Mount Tamalpais, Point Reyes National Seashore, Henry Cowell Redwoods State Park, and Big Basin Redwoods State Park gave him opportunities to approach victims away from witnesses.
Carpenter was ultimately convicted of seven murders committed between October 1980 and May 1981. Decades later, DNA evidence also connected him to the 1979 murder of Mary Frances Bennett in San Francisco, making her another firmly linked victim even though Carpenter was never prosecuted for her death. Investigators have suspected him in additional killings, although those cases were never proven in court.
A Long History of Violence Before the Murders
Carpenter's violent criminal history began many years before the Trailside murders. In 1960, he attacked a woman in the Presidio of San Francisco with a knife and hammer. When a military police officer intervened, Carpenter fired a tear-gas gun at the officer. The woman survived, and Carpenter was convicted and imprisoned.
After his release, Carpenter returned to violent crime. During January and February 1970, he committed a series of attacks in Northern California. On January 27, he confronted a woman on an isolated Santa Cruz County road, attempted to rape her, and stabbed her three times. The following day he broke into a home in the Santa Cruz Mountains, abducted a woman at gunpoint, tied her hands, drove her elsewhere, and raped her. On January 29, he confronted another woman at gunpoint in Daly City, bound her hands, and stole her automobile.
On February 3, 1970, Carpenter robbed another woman at gunpoint in Calaveras County and stole her vehicle. Later that day, he abducted a woman and her infant son from their home in Angels Camp. He forced the woman to drive to an isolated location and raped her. Carpenter was convicted of crimes arising from this period and returned to prison. He was also convicted of escaping from the Calaveras County jail.
Despite this extensive record of violence against women, Carpenter was eventually released again. By 1979 he was back in the San Francisco Bay Area. It was during this period that a succession of women began disappearing or being found murdered in or near parks and hiking trails.
The Beginning of the Trailside Murders
The attacks that became associated with Carpenter were particularly frightening because they occurred in places normally associated with recreation and solitude. Victims were hikers, joggers, students, or young people simply spending time outdoors. Remote trails allowed the killer to approach without attracting attention and to move victims away from areas where other hikers might see what was happening.
Early investigators referred to the unknown offender as the "Mount Tam Killer" because several crimes occurred around Mount Tamalpais. As the attacks spread to additional parks, the more familiar name "Trailside Killer" came into use.
Mary Frances Bennett - October 21, 1979
One of Carpenter's earliest firmly established murder victims was 23-year-old Mary Frances Bennett. On October 21, 1979, Bennett went jogging at Lands End in San Francisco, near the Palace of the Legion of Honor. She was attacked in the wooded recreation area and stabbed repeatedly. Her body was concealed beneath dirt, branches, and vegetation and was discovered later that day.
Carpenter became a suspect after his eventual arrest in 1981, but investigators did not have enough evidence at the time to charge him with Bennett's murder. The case remained unresolved for nearly three decades. In 2009, San Francisco cold-case investigators reexamined preserved evidence using modern DNA technology. The resulting profile matched Carpenter. Police publicly announced the DNA connection in February 2010. Because Carpenter was already under multiple death sentences, he was not subsequently tried for Bennett's murder.
The Point Reyes Murders of Richard Stowers and Cynthia Moreland
On October 11, 1980, 19-year-old Richard Edward Stowers and his 18-year-old fiancee, Cynthia Toshiko Moreland, went hiking at Point Reyes National Seashore in Marin County. During the early afternoon, other hikers heard gunshots in the heavily wooded area.
Stowers and Moreland failed to return. Their disappearance remained unresolved for weeks. On November 29, 1980, their bodies were discovered near a hiking trail at Point Reyes. Both had been fatally shot in the head and were lying near one another. The location would prove especially significant because two more murder victims were discovered nearby.
The Murder of Anne Alderson
Anne Evelyn Alderson, 26, was killed on October 13, 1980, near a hiking trail on Mount Tamalpais. She was last seen alive at approximately 5:30 that evening. Her body was discovered two days later, on October 15.
Alderson had been shot in the head at close range. Evidence recovered during the investigation indicated that she had been sexually assaulted around the time of her death. Carpenter was later convicted not only of Alderson's murder but also of raping her.
Alderson's case is sometimes incorrectly listed with October 15 as her murder date because that was the date her body was discovered. Court records establish that she was killed on October 13, 1980.
The Murders of Diane O'Connell and Shauna May
On November 28, 1980, Diane Marie O'Connell, 22, and Shauna Catherine May were killed at Point Reyes National Seashore. Hikers reported hearing gunfire during the afternoon. The following day, searchers discovered O'Connell and May lying near one another in a wooded area.
The location was only about 200 yards from the bodies of Richard Stowers and Cynthia Moreland, which were also discovered during the search. The discovery of four murder victims in the same general section of Point Reyes made it increasingly clear that investigators were dealing with a serial predator.
O'Connell and May had both been fatally shot in the head. Evidence indicated that O'Connell had also been strangled. Carpenter was eventually convicted of attempting to rape O'Connell before killing her. He was convicted of raping May and murdering her.
The Attack on Ellen Hansen and Steven Haertle
On March 29, 1981, University of California, Davis students Ellen Marie Hansen and Steven Russell Haertle, both 20, were camping at Henry Cowell Redwoods State Park in Santa Cruz County. That afternoon, they went hiking along the Ridge Trail toward the Cathedral Redwoods.
They encountered Carpenter on the trail. After initially passing the couple, he confronted them again, produced a revolver, and ordered them to obey him. Carpenter made his intention to sexually assault Hansen clear. Hansen resisted his demands, and Carpenter opened fire.
Hansen was struck by multiple bullets, including shots to her head, and died at the scene. Haertle was shot through the neck and seriously wounded but survived. After regaining consciousness, he escaped and reached other hikers who summoned help.
Haertle's survival became one of the most important developments in the entire investigation. He had seen the attacker at close range and was able to provide investigators with a description. He later identified Carpenter as the gunman. Other people in the park had also seen the suspicious man and a red Fiat associated with him, providing additional evidence.
The Murder of Heather Scaggs
Heather Roxanne Scaggs, 20, worked with Carpenter at a trade school in Hayward and lived in San Jose. On May 2, 1981, Scaggs planned to travel to Santa Cruz with Carpenter because she hoped to purchase a vehicle from one of his acquaintances. She left home that morning and was never seen alive again.
When Scaggs did not return, friends questioned Carpenter. He acknowledged that the two had planned to travel together but claimed that he had overslept, experienced automobile trouble, and never met her.
On May 24, 1981, hikers discovered Scaggs's body in mountainous wooded terrain in Big Basin Redwoods State Park in Santa Cruz County. She had been sexually assaulted and shot at close range. Ballistics evidence established that the same .38-caliber Rossi revolver used against Ellen Hansen and Steven Haertle had been used to murder Scaggs.
Known and DNA-Linked Murder Victims
- Mary Frances Bennett, 23 - October 21, 1979 - Lands End, San Francisco, California. Bennett was attacked while jogging and stabbed repeatedly. Carpenter was not convicted in this case, but preserved evidence produced a DNA match to him decades later, and police announced the identification in 2010.
- Cynthia Toshiko Moreland, 18 - October 11, 1980 - Point Reyes National Seashore, Marin County, California. Moreland was fatally shot while hiking with her fiance, Richard Stowers. Their bodies were discovered on November 29, 1980.
- Richard Edward Stowers, 19 - October 11, 1980 - Point Reyes National Seashore, Marin County, California. Stowers was shot and killed with Cynthia Moreland. Carpenter was convicted of both murders.
- Anne Evelyn Alderson, 26 - October 13, 1980 - Mount Tamalpais, Marin County, California. Alderson was sexually assaulted and fatally shot at close range. Her body was discovered on October 15, 1980. Carpenter was convicted of rape and murder.
- Diane Marie O'Connell, 22 - November 28, 1980 - Point Reyes National Seashore, Marin County, California. O'Connell was shot to death and evidence indicated that she had also been strangled. Carpenter was convicted of her murder and attempted rape.
- Shauna Catherine May - November 28, 1980 - Point Reyes National Seashore, Marin County, California. May was sexually assaulted and shot to death. Her body was discovered on November 29 near O'Connell and only a short distance from the bodies of Stowers and Moreland. Carpenter was convicted of rape and murder.
- Ellen Marie Hansen, 20 - March 29, 1981 - Henry Cowell Redwoods State Park, Santa Cruz County, California. Hansen was shot and killed after Carpenter confronted her and Steven Haertle on a hiking trail and announced his intention to rape her. Haertle was shot but survived. Carpenter was convicted of Hansen's murder and attempted rape and of attempting to murder Haertle.
- Heather Roxanne Scaggs, 20 - May 2, 1981 - Big Basin Redwoods State Park, Santa Cruz County, California. Scaggs disappeared after arranging to travel to Santa Cruz with Carpenter. Her body was discovered on May 24. She had been sexually assaulted and shot. Carpenter was convicted of rape and murder.
Other Murders Investigated as Possible Carpenter Crimes
Several additional deaths were investigated for possible connections to Carpenter. These cases should be distinguished from the seven murders for which he was convicted and the Bennett murder later connected to him by DNA. Carpenter was never convicted of the following crimes, and the available evidence did not establish his guilt beyond a reasonable doubt.
- Edda Kane, 44 - Kane disappeared while hiking at Mount Tamalpais on August 19, 1979, and was found dead on August 20. She had been shot in the head. Carpenter became a major suspect, but he was never charged with her murder. Because she disappeared the previous day, the exact time of her death is less certain than the date her body was found.
- Barbara Ann Schwartz, 23 - March 8, 1980 - Mount Tamalpais, Marin County, California. Schwartz was attacked and stabbed to death while walking in the Mount Tamalpais area. Authorities investigated Carpenter as a suspect, but he was never prosecuted for her death.
- Anna Kelly Menjivar, 17 - Menjivar disappeared from Daly City on December 28, 1980. Her partial skeletal remains were discovered in the Castle Rock State Park area on June 16, 1981. The condition of the remains prevented investigators from determining a definite cause or exact date of death. Carpenter was investigated because he had frequented the bank where Menjivar worked and was known to have spoken with her, but no murder charge was filed.
The Weapon That Connected the Murders
One of the strongest pieces of physical evidence against Carpenter was a .38-caliber Rossi revolver. A woman who knew Carpenter testified that she purchased the firearm at his request and gave it to him. Carpenter paid for the weapon.
Ballistics examinations established that the Rossi had fired bullets involved in the Santa Cruz crimes against Ellen Hansen, Steven Haertle, and Heather Scaggs. Investigators also established that the same firearm had been used in the Marin County murders for which Carpenter was later prosecuted.
Shortly before his arrest, Carpenter gave the revolver to an acquaintance. The weapon was eventually hidden in a vacant San Francisco lot. Investigators recovered it after being shown its location. The ballistics connection gave prosecutors a physical link tying together crimes committed many miles apart.
Eyewitness Evidence and Carpenter's Identification
Steven Haertle provided investigators with crucial firsthand evidence because he had survived Carpenter's March 29 attack. Haertle positively identified Carpenter during a physical lineup and again in court. Other witnesses from Henry Cowell Redwoods State Park also connected Carpenter to the man seen near the shooting scene.
Witnesses described the attacker wearing a distinctive gold-colored jacket and a baseball cap. Testimony established that Carpenter had access to an unusual gold jacket of the same general appearance. Witnesses also reported a red Fiat leaving the area after the Hansen shooting, and Carpenter owned a similar vehicle.
Investigators additionally found that Carpenter had purchased Nike shoes immediately before the Hansen attack that were consistent in size and tread pattern with footprints left by the gunman. No single piece of circumstantial evidence established the entire case, but the eyewitness identifications, vehicle, clothing, footwear evidence, firearm evidence, and Carpenter's connections to particular victims formed an increasingly powerful case.
Arrest and the End of the Trailside Murders
By the spring of 1981, law enforcement agencies from several Northern California jurisdictions were cooperating in an increasingly intensive search for the Trailside Killer. Information from witnesses and people familiar with Carpenter focused attention on the convicted violent offender living in San Francisco.
Carpenter was arrested in mid-May 1981. At the time, Heather Scaggs was still missing. Her body was discovered nine days later, and forensic examination connected her killing to the same firearm used in the Hansen attack.
The investigation crossed county lines and eventually produced separate prosecutions because the murders had occurred in different jurisdictions. Intense publicity surrounding the Trailside killings also made it difficult to select local juries, leading to changes of venue for Carpenter's trials.
The 1984 Santa Cruz County Murder Trial
Carpenter's first major murder trial involved the crimes against Ellen Hansen, Steven Haertle, and Heather Scaggs. Because of extensive publicity in Northern California, the case was tried in Los Angeles County.
The jury found Carpenter guilty of the first-degree murders of Hansen and Scaggs. He was also convicted of attempting to rape Hansen, attempting to murder Haertle, and raping Scaggs. Jurors found special circumstances making Carpenter eligible for capital punishment.
On November 16, 1984, the court formally sentenced Carpenter to death for the Santa Cruz County murders.
The 1988 Marin County Murder Trial
Carpenter still faced prosecution for five murders committed in Marin County. Because of the extraordinary publicity surrounding the case, that prosecution was moved to San Diego County.
On May 10, 1988, a jury convicted Carpenter of the first-degree murders of Cynthia Moreland, Richard Stowers, Anne Alderson, Diane O'Connell, and Shauna May. He was also convicted of raping Alderson and May and attempting to rape O'Connell. The jury found that Carpenter had personally used a firearm and that the murders involved special circumstances.
The jury recommended another death sentence. On July 19, 1988, the court formally imposed the second judgment of death against Carpenter.
Appeals and Imprisonment
Carpenter's convictions produced years of appeals and post-conviction litigation. The California Supreme Court affirmed the judgment arising from his Santa Cruz County crimes in 1997. In 1999, the court affirmed the judgment for the five Marin County murders.
Carpenter therefore remained legally convicted of seven murders, in addition to the later DNA evidence identifying him as Mary Frances Bennett's killer. He has spent decades as a condemned California prisoner. As of 2026, Carpenter remains incarcerated at the California Health Care Facility in Stockton under his death sentences.
The Lasting Impact of the Trailside Killer
The Trailside murders altered the atmosphere of Northern California's parks. Places that had represented solitude, recreation, and natural beauty suddenly became associated with the possibility of a predator hiding along an isolated trail. During the height of the investigation, warnings about hiking alone became common, and fear of another attack caused many people to avoid trails where they had once felt safe.
Carpenter's case is also notable for the combination of evidence ultimately used against him. A surviving eyewitness, forensic ballistics, witness observations, a distinctive vehicle and clothing, physical evidence, and the recovery of the murder weapon helped prosecutors connect killings scattered across multiple parks and counties. Nearly thirty years later, improved DNA technology added Mary Frances Bennett to the established record of Carpenter's violence.
David Joseph Carpenter's known history demonstrates that the Trailside murders were not an abrupt beginning to his violence. Years before he became known as a serial killer, he had already attacked, kidnapped, sexually assaulted, and threatened women and had repeatedly returned to violent crime after release from custody. His later murders transformed that history into a prolonged series of killings that terrorized Northern California and left at least eight families with deaths now directly tied to him through convictions or forensic evidence.
