Warren Leslie Forrest was born on June 29, 1949, in Vancouver, Washington. He graduated from Fort Vancouver High School in 1967, where he was the captain of the track and field team. After serving in the U.S. Army during the Vietnam War, Forrest returned to Washington and married his high school sweetheart, Sharon Ann Hart, in 1969. They had two children. Forrest worked for the Clark County Parks Department and lived in Battle Ground, Washington.

Between 1971 and 1974, a series of disappearances and murders of young women occurred in Clark County, Washington. Forrest was first arrested on October 2, 1974, after a 20-year-old woman survived an attack where she was raped, tortured with an air-powered dart gun, and stabbed near Lacamas Lake. Her detailed description led to Forrest's arrest.

In 1976, the skeletal remains of 20-year-old Krista Blake were discovered on Tukes Mountain. Witnesses had seen her entering a blue Ford van driven by a man matching Forrest's description. In 1979, Forrest was convicted of Blake's murder and sentenced to life imprisonment.

In 2015, remains found in 1974 were identified as 17-year-old Martha Morrison. DNA evidence linked blood found on Forrest's dart gun to Morrison, leading to his conviction in 2023.

Forrest is suspected in several other cases, including the disappearances and murders of Jamie Grissim (16), Barbara Ann Derry (18), Diane Gilchrist (14), Gloria Nadine Knutson (19), and Carol Valenzuela (20). Many of these victims were last seen hitchhiking and were found in remote areas of Clark County.

Despite multiple parole hearings, Forrest has remained incarcerated, with authorities citing the severity of his crimes and the likelihood of his involvement in additional unsolved cases.