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Crime Solvers Central
298 Cases Solved. Advancing justice for missing persons, unsolved homicides, unidentified and unclaimed remains.

Case Description

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Summary based on the NamUs case record (MP13616) and 6 other sources
The start of a new year brought a somber mystery to Portland, Oregon, in 1989 with the disappearance of 35-year-old Marilyn Sue Koski. In the early hours of January 1st, Marilyn, a resident of a houseboat on the Willamette River, vanished. She was a woman with a notable educational background, holding degrees from both Brigham Young University and Oregon State University, and had previously dedicated her time to teaching physical education and health. Concern for her well-being grew after two notes were discovered, one addressed to her next-of-kin and another to her roommate. The contents of these notes were alarming, as they suggested the possibility of self-harm. The last known description of Marilyn indicated she was wearing blue jeans, a pink and white shirt, a gray sweatshirt, and a purple and blue jacket, along with fur boots.

Following the discovery of the notes, an immediate search was launched by authorities. The focus of their efforts was the Willamette River, given that Marilyn's home was a houseboat and the distressing nature of the notes she left behind. Investigators held the belief that she may have entered the water, leading to an extensive search of the river near her houseboat. Despite their diligent efforts, the search of the Willamette River yielded no signs of Marilyn. Her body was never recovered, leaving a painful void for those who knew her and a lingering question for law enforcement. In the absence of any further evidence or contact, her loved ones held a memorial service for her later that same month, grappling with the profound uncertainty of her fate.

The disappearance of Marilyn Sue Koski has since become a long-standing cold case for the Multnomah County Sheriff's Office. With no new leads or evidence emerging over the decades, her case remains open, a silent testament to a life interrupted. The details of her disappearance, from the notes left behind to the fruitless search of the river, paint a sorrowful picture. Authorities believe she may have drowned, but without the recovery of her remains, this can only be considered a strong possibility, not a definitive conclusion. The case is a poignant reminder of the many individuals whose stories end without a final chapter, leaving families and communities to navigate an enduring sense of loss and the torment of unanswered questions.

Last Seen: Jan 1, 1989

Possible Unidentified Matches (2)

Unidentified remains cases whose details are consistent with this person, ranked by how closely they compare. Fields that are unknown in either case are left out of the score.

81%Moderate
Jane Doe — Portland, Oregon - unidentified case UP9599
Jane Doe — Portland, Oregon
UP9599 • Found Sep 7, 1993
View case
Sex ✓Female
Age 100%Est. 30–40 vs 35 when missing
Race 100%White
Location 100%Same area, same county
TimingFound 5 years after last seen
Height 100%5'4" vs 5'2"–5'4"
Weight 100%140 lb vs 130–140 lb
Hair 50%Brown vs Blond
Eyes 0%Brown vs Blue
77%Possible
Jane Doe — Portland, Oregon - unidentified case UP9936
Jane Doe — Portland, Oregon
UP9936 • Found Oct 18, 1994
View case
Sex ✓Female
Age 85%Est. 35–55 vs 35 when missing
Race 100%White
Location 100%Same area, same county
TimingFound 6 years after last seen
Height 84%5'6" vs 5'2"–5'4"
Weight 100%130 lb vs 130–140 lb
Hair 50%Brown vs Blond
Eyes 0%Brown vs Blue

These comparisons are generated automatically from public NamUs case data and are not confirmed identifications. Only DNA, dental or fingerprint comparison by investigators can confirm an identity. If you believe two cases are connected, contact the agency handling the unidentified case.

Unidentified photos are blurred because many are post-mortem. Tap a photo to reveal it.