Suspected serial killer Warren Forrest appeared Monday in Clark County Superior Court to face a new murder charge in the slaying of a teenage girl in the 1970s.

The 70-year-old man — who’s already serving a life sentence in the Washington State Penitentiary in Walla Walla for the 1974 murder of another Vancouver, Wash., woman — is facing charges of first-degree murder in Martha Morrison’s death. The 17-year-old Portland girl’s body was found in Dole Valley in 1974.

Although he’s not subject to release, Forrest’s bail was set at $5 million. If he posts, he’ll be sent back to the Washington State Penitentiary in Walla Walla.

Investigators saw a breakthrough in the cold case in 2015, when blood found on an air pistol Forrest used to torture yet another woman in 1974 was identified as Morrison’s.

The Battle Ground man is suspected of killing at least six women and girls in the area. But he’s only been convicted of one murder: that of 19-year-old Krista Blake, who was last seen July 11, 1974, climbing into Forrest’s light blue Ford Econoline cargo van near downtown Vancouver. She had hitchhiked from Battle Ground and prearranged to meet the driver for a ride to Portland, according to court records.

Blake’s body was found two years later in a shallow grave on the grounds of the Tukes Mountain Maintenance Facility, operated by the Clark County Parks Department, about a mile east of Battle Ground. She was strangled and stabbed to death, court documents say.

Forrest lived about 2.5 miles from the facility and was employed as a maintenance worker for the parks department. It would take five years before he would be convicted in Blake’s death.