David Joseph Carpenter (born May 6, 1930), a.k.a. the Trailside Killer, is an American serial killer known for stalking and murdering a variety of individuals on hiking trails in state parks near San Francisco, California. Carpenter killed at least ten individuals, with two attempted victims, Steven Haertle and Lois Rinna, surviving. He used a .38 caliber handgun in all but one of the killings; a .44 caliber handgun was used in the killing of Edda Kane on Mount Tamalpais.
David Carpenter, a native of San Francisco, was physically abused as a child by his alcoholic father and domineering mother. As a boy, he had a severe stutter, a persistent bed-wetting problem, and exhibited cruelty to animals. At age 13, Carpenter was incarcerated for molesting two of his cousins. He married in 1955, in a union that produced three children.
Carpenter first attempted murder in 1960, for which he spent seven years in prison. This was committed against Lois Rinna, mother of celebrity Lisa Rinna. In 1970, he was arrested for kidnapping and spent a further seven years behind bars. After his release, he was suspected of possibly being the Zodiac Killer, although he was eventually cleared.
From 1979–1981, Carpenter raped and murdered five women in Santa Cruz and Marin counties. His composite sketches were drawn by retired Marin County Sheriff's Department detective Edmond Mauberret. On May 10, 1988, a San Diego jury convicted him on five counts of first-degree murder in the slayings of Richard Stowers, Cynthia Moreland, Shauna May, Diane O'Connell and Anne Alderson. Carpenter also was found guilty of raping two of the women and attempting to rape a third. He was sentenced to die in the gas chamber, and remains on San Quentin's death row.
Following his conviction for the Marin County murders, Carpenter was tried, and subsequently convicted, by a Santa Cruz jury for the murders of two other women, Ellen Hansen and Heather Scaggs. The same jury also found Carpenter guilty of the attempted murder of Hansen's hiking companion Steven Haertle, the attempted rape of Hansen, and the rape of Scaggs. Hansen, who was a University of California-Davis student, has a memorial scholarship created in honor of her courage during the attack, which allowed Haertle to escape alive. In 1995, the Santa Cruz convictions were overturned due to juror misconduct. The California Supreme Court later reinstated the Santa Cruz convictions.
In December 2009, San Francisco police reexamined evidence from the October 21, 1979, murder of Mary Frances Bennett, who was jogging at Lands End when she was attacked and stabbed to death. A DNA sample obtained from the evidence was matched to Carpenter through state Department of Justice files. In February 2010, police confirmed the match with a recently obtained sample from Carpenter.
Carpenter is still a suspect in the murders of Edda Kane and Barbara Schwartz.