Remembering the Serial Killer Who Terrorized Northern California Hikers in the 1980’s

In the wake of the arrest of the notorious Trailside Killer, the people of Marin County could finally breathe a sigh of relief. Parks were once again filled with hikers and visitors, as the bright orange “DO NOT HIKE ALONE” signs were taken down.

For 21 months, from 1979 to 1981, the hiking trails of Marin County and Santa Cruz County had been terrorized by an unknown killer. Ultimately, the man behind these heinous acts was arrested in May 1981, in large part due to the survival of one of his last murder victim’s boyfriends.

David Joseph Carpenter, a repeat sex offender, had a criminal record dating back decades. Due to bureaucratic oversights, he was not on California’s sex-offender registry or the state’s list of recently released prisoners given to Marin County investigators. The first tip that led authorities to Carpenter came from a woman who had encountered him on a cruise 26 years earlier.

Carpenter would be convicted in two Southern California trials for most of the Trailside killings, but a full accounting of his crimes would not be made until 2010. DNA evidence linked him to the 1979 Lands End murder of jogger Mary Frances Bennett, whose body had been found stabbed at least 25 times and buried under a thin layer of dirt and branches.

The height of the hiking murders occurred 40 years ago in October-November 1980. Four people were found shot to death with the same .38-caliber pistol on Sky Trail at Point Reyes: Cynthia Moreland, 18, and fiancé Richard Stowers, 19; Diane O’Connell, 22; and Shauna May, 23. In October 1980, Anne Evelyn Alderson, 26, was raped and shot dead on a Mount Tam trail with the same pistol. Carpenter was also suspected of killing two hikers there several months earlier: Edda Kane, 44, and Barbara Schwartz, 23.

As the investigation into the murders progressed, authorities initially developed a profile of the killer, believing him to be a handsome man aged 28 to 35 years old with a “winning personality” who didn’t initially frighten his victims. This hypothesis turned out to be far from the truth.

Carpenter’s capture finally came after the last victim, Heather Scaggs, was killed. Scaggs had been a student at the same Hayward trade school where Carpenter worked as a printer. Her body was found, raped and shot, by hikers in Big Basin State Park. After Scaggs’ disappearance, the evidence began to close in around Carpenter, who had evaded suspicion despite being on parole with a long history of sex crimes.

Carpenter was arrested and charged with multiple murders, including those of Hansen and Scaggs. In July 1981, police recovered the .38-caliber gun used in seven of the Trailside killings from a San Francisco construction site, tracing it to Carpenter.

The case of the Trailside Killer exposed alarming oversights in the criminal justice system. Carpenter’s long criminal history and potential for further violence should have been red flags for authorities. But because he was not on the state’s sex-offender registry or list of recently released prisoners, he was not initially considered a suspect.

Carpenter was tried separately for the murders in Santa Cruz and Marin Counties. He received the death penalty in both convictions, the last of which was in 1988. At 90 years old, Carpenter remains the oldest inmate on San Quentin’s Death Row, continuing to deny his involvement in the murders.