PORTLAND, Ore. (KOIN)– In less than two weeks, a suspected serial killer is scheduled to finally stand trial for the killing of Portland teenager Martha Morrison in 1974.

If Warren Forrest is found guilty, it will only be his second murder conviction, even though he’s suspected of killing seven women and girls from Portland and Clark County, and attacking two more who survived.

Morrison’s case is coming to trial, partially due to KOIN 6 News pushing investigators to find Morrison’s remains, which had been mislabeled in the evidence warehouse. The case against Forrest now is based on critical DNA evidence his lawyer doesn’t want to be allowed in court. Without that evidence from nearly 50 years ago, the case may be impossible to prove.

Now 73 years old, Forrest was recently back in the Clark County courthouse, where he was convicted in 1979 for the kidnapping and murder of Krista Blake near Battle Ground in July of 1974.

Most recently, Forrest’s lawyer argued he should not be prosecuted for the murder of Morrison in October of 1974 because many of the witnesses have died, including Forrest’s parents, who could provide an alibi that he was working weekends at their beach house. The judge, however, did not agree.

“I don’t think Mr. Forrest claimed he had witnesses who could account for his whereabouts 24 hours a day,” said Judge Robert Lewis, Clark County Superior Court.

Forrest’s lawyer also told the judge it would not be fair for the jury to hear about other attacks — Forrest admitted in sex offender therapy to “a minimum of four additional victims that he lured into his vehicle, drove to a remote location and raped.”

Court documents say Forrest told the prison therapist his first attack was against a woman in Texas while he was in the Army around the age of 20. Forrest also made problematic statements to the parole board, saying that he attacked women to cope with feelings of worthlessness and hopelessness.

“All I had in mind was a distraction and the distractions (were) deviant fantasies, and the deviant fantasies distracted me from my everyday life. But then it led me to my crimes,” Forrest told the panel on May 18, 2022, before the board denied him parole for the murder of Blake.

The judge ruled things Forrest said in parole hearings and sex offender treatment about other unadjudicated victims will not be allowed at trial.

The defense argued jurors should not be allowed to hear about evidence from Forrest’s previous convictions, including the kidnapping of a 20-year-old woman from Portland who he took to Lacamas Lake, brutally raped, and left for dead. Evidence from that attack is what ties Forrest now to the murder of Morrison.

Forrest, a former county parks employee, admitted to using a dart gun to shoot the Lacamas Lake victim on Oct. 1, 1974.

In 2015, through DNA, the Washington State Crime Lab identified a stain on the dart gun as Morrison’s blood. Her body was found 20 miles away from Lacamas Lake, in remote NE Clark County in a clearing off of Dole Valley Road.

“If it comes out at trial, it’s going to be what the jury focuses on. That’s really going to be the state’s entire case… That’s why it’s so grossly prejudicial to Mr. Forrest,” said Sean Downs, Forrest’s attorney.

In the end, the judge decided that the dart gun and other Lacamas Lake evidence can be used against Forrest when he faces a new jury, 48 years after Morrison disappeared.

The trial is scheduled to start on Jan. 23. Forrest was initially charged in 2019, but the pandemic delayed the trial multiple times. Additional delays were caused when the lead prosecutor became a judge. A hearing will happen on Jan. 12 to decide if both sides are ready to proceed.