VANCOUVER, Wash. (KOIN) — Jerri Mitchell thinks about Diane Gilchrist a lot, especially on Aug. 8, which would be their 59th birthdays — if Diane is still alive.

“I miss her, I’ve missed her all these years,” Jerri said. “She was my first real friend.”

Diane disappeared 44 years ago. She was just 14 years old.

KOIN 6 News was the first to report this past February that detectives now believe she’s a victim of suspected serial killer Warren Forrest.

Why detectives think Diane Gilchrist is Warren Forrest’s 9th victim

The only known photo of Diane Gilchrist. (KOIN)

For all these years, Jerri has hoped her best friend ran away to live another life.

They were 9th graders at Shumway Junior High School in downtown Vancouver. Both had rough childhoods.

“When Diane came along, she just came out of nowhere,” Jerri said. “I don’t remember her being in school before, we just ended up being friends and we hit it off and then she disappeared.”

Diane and her family lived in a house on Franklin Street. In the spring of 1974, detectives say Diane snuck out the top window and vanished.

But after four decades, Clark County detectives say they now think she was kidnapped and killed by Warren Forrest. If true, she would be his 9th victim — and the 7th who didn’t survive.

What Diane looked like when she disappeared compared to a photo of what she may look like now.

Forrest is only in prison for one murder. A year ago, KOIN 6 News reported a stunning breakthrough on two of the other unsolved cases. DNA finally linked Forrest’s attack on a woman who survived to the bodies of two other women. Right now, detectives are working with the prosecutor, hoping to charge Forrest with those crimes. But that high-tech DNA discovery isn’t why detectives now suspect Forrest in Diane’s death.

If you plot Forrest’s suspected attacks on a calendar and map, you can see why investigators think the odds someone else took Diane are so small.

  • Diane disappeared from downtown Vancouver on May 29, 1974.

  • Two days later, Gloria Knutson also disappeared from downtown Vancouver.

  • In July of 1974, Krista Blake disappeared in downtown Vancouver.

  • Six days later, Norma Countryman was abducted while hitchhiking in Ridgefield.

  • Two weeks after that, Carol Valenzuela was last seen in downtown Vancouver.

Convicted killer Warren Forrest at his parole hearing, July 18, 2017 (KOIN)

Detectives believe the time and place show a pattern of a man who acts out when he can no longer control his urges — something Forrest seemed to admit at his patrol hearing in 2017.

“I more of less felt that my only option was a distraction and the distraction I chose was deviant fantasies,” Forrest said. “And my crime was living out one of those fantasies.”

However, Forrest has never talked about other attacks and unsolved cases from so many years ago, including Diane — who disappeared without a trace.

“I’ve always though of kids like her and I, we get lost in the world,” Jerri said. “We are the ones that if we disappear, no one cares. And that’s what I saw with Diane. Nobody cared when she disappeared. I never had anyone come ask me. I was her best friend when she disappeared.”

Jerri also said that if Diane was one of Forrest’s victims, “at least there’s knowing what happened to her” and knowing she wasn’t forgotten.

The girl who was Forrest’s first suspected victim has also never been found: 16-year-old Jamie Grissim.

The sheriff’s office has been working with the Clark County prosecutor for months to figure out if they can charge Forrest with double murder in two of the other cases.

Suspected victims:

  • Jamie Grissim: Dec 7, 1971, last seen in Vancouver, still missing. ID found on Dole Valley Road, Clark County.

  • Barbara Ann Derry:  Feb 11, 1972, last seen hitchhiking on SR-14. Body found March 29, 1972 at Grist Mill.

  • Diane Gilchrist: May 29, 1974, last seen in downtown Vancouver. Still missing.

  • Gloria Knutson: May 31, 1974, last seen in downtown Vancouver.

  • Krista Blake: July 11, 1974, last seen downtown near 29th and K getting into a blue van. Warren Forrest drove a blue van. Body found Tukes Mountain in Battle Ground.

  • Norma Country: July 17, 1974, abducted while hitch hiking in Ridgefield. Escaped from Tukes Mountain. 

  • Carol Valenzuela:  Aug. 2, 1974, last seen in downtown Vancouver. Body found next to Martha Morrison off Dole Valley Road.

  • 21-year-old woman: Oct. 1, 1974, abducted in downtown. Survived attack at Lacamas Lake.

  • Martha Morrison: Disappeared sometime in 1974. Possibly Portland. Oct. 12, 1974, bones found next to Carol Valenzuel off Dole Valley Road. Remains weren’t identified until 2015