May 21, 2025 7:58 pm

The premier news source for Snohomish County

Sheriff’s Office seeking tips to crack cold case of the Pinnacle Lake double homicide

GRANITE FALLS—On July 11, 2006, Mary Cooper, 56, and her daughter Susanna Stodden, 27, went hiking on the Pinnacle Lake Trail near Granite Falls. Later that day, mere hours after they had left their home early that morning, they were both found shot dead in the head on the trail.

Pinnacle Lake
Mary Cooper (left), 56, and her daughter Susanna Stodden (right), 27, who were killed on Pinnacle Lake Trail near Granite Falls.

Both of the women’s clothing had been partially removed. Mary’s husband David suspected it was an attempted sexual assault that had gone wrong telling reporters working for King 5 back in January that they were both “pretty strong people.”

David was a suspect for a long time and was even given a polygraph test, which he passed. Infuriated by the Snohomish County Sheriff’s Office, whose investigation he called a “failure” in an Everett Herald advert, he decided to take measures into his own hands.

David Stodden worked on a documentary film about the murders, teaming up with Seattle-based Investigative Films and is now offering a $1,000 reward for anyone who can forward with information that will solve his wife and daughter’s murder.

Pinnacle Lake
Mary Cooper, 56, and husband David Stodden.

Detectives working for the Snohomish County Sheriff’s Office 18 years later, are still seeking tips that could lead to solving the cold case.

The Pinnacle Lake Trail is in the Snoqualmie-Mt Baker National Forest off the Mountain Loop Highway, east of Granite Falls and Verlot.

Mary Cooper and her daughter Susanna’s ashes were sprinkled on Mount Kilimanjaro in Africa, the Grand Canyon, the Colorado River, and at the home garden in the Seattle neighborhood of Green Lake. There was an estimated 1,500 people at their memorial service.

Mary was a school librarian and was described by family as being a “voracious reader.” When she was growing up her father took her on plenty of hikes and she decided to raise her children the same. Susanna, her daughter, quickly followed suit and formed an avid bond with the great outdoors.

Susanna had just turned 27 a week before she was killed. She graduated from Western Washington University with a degree an Environmental Studies in 2011 and spent a semester teaching in Nepal before returning to Seattle to work in a non-profit that teaches children about nature.

The mother and daughter had spoken about their plans of hiking Mount Pilchuck leading up to that fateful day with Mary’s women’s group. During that group, Mary had mentioned how excited she was to spend a day hiking with her first-born daughter.

It was reported that the mother and daughter changed their itinerary that morning, deciding to hike Pinnacle Lake instead out of fear there would still be snow on Mount Pilchuck.

It was an early morning and there were very few cars in the parking lot that day. Before embarking up the trailhead, Susanna and Mary spoke to a couple right outside the parking lot, who told officers they remember hearing what sounded like “thunder” up the mountains, wondering if what they heard were gunshots.

Mary and Susanna’s bodies were found by a hiker around 2:30 p.m. that day. He hurried back to a nearby campsite to call for help.

Back in Seattle, David Stodden began to grow worried the later the day grew. He called the Washington State Patrol and the Snohomish County Sheriff’s Office. He recalls Officers showing up and being questioned, his car’s odometer read, before they broke the news.

David cooperated with the police, turning over computers, checkbooks, and life insurance policies. He has not stopped seeking to solve the murder of his wife and daughter.

David and Mary met each other while studying at the University of Washington. They had been married for 30 years.

Anyone with information or tips related to this investigation is asked to call the Sheriff’s Office tipline at 425-388-3845.

Kienan Briscoe
Author: Kienan Briscoe

2 Responses

  1. I worked with Susanna Stodden in 1996 and just found out a few weeks ago that she was murdered in 2006 along with her mother. I was listening to a true crime podcast a few days ago and heard of a similar case involving a Snohomish man named Terrence Miller. In 2020, through DNA evidence, Miller was found guilty of the cold case murder of Jody Loomis in 1972. The crimes are similar, in that Jody was riding her bicycle in a wooded area when she was sexually assaulted, then shot in the head with a .22 caliber pistol.

    1. These kind of persons they re scouting after victims. Victims of all kinds but children and women are the must vulnerable people and people that lives in areas with a low socioeconomy. People who work late hours and in shift and take the bus more likely than a car.
      But the killers prefer people that sims to ”have everything” people who sims to enjoy life and show up With a sprakling soul. But they take what is possible.
      These people are sick and dangerous and they can live next door or be your daughters friends father.
      They can join the searching team the team that are out and looking for a missing person maybe a child they can go next to the mother of that child EVEN if they are innocent – why? They enjoy to be in the dramafield they get kicks of all kinds of drama and when people suffer and get hurt. They operate very well in these fields and collect all the gold there is.
      They sims to be the nice Guy and sometimes they turn up like heros – they love that role. They are the most greatest Actor you can find on the planet. They are full of lies and bs and they have a hard core criminalrecord from an early age. And everyting on that record isnt registred at the police office sometimes it s totally blank there.

      They Want to look good many want s that but here its extreme. And they Want you to belive that they are very smart.

      Many innocent persons that are very close to a victum maybe a familymember have bad experience when it comes to inturegation at the police its very sad. But a reminder !!! the killer can be anyone and sometimes sims to be the most timid person in the World even look like a boyscout. And the familymembers the cloes once to the victims and the police have the same goal.
      And its importent that Everyone is on the same page and that it is the right person or persons that get caught.
      Wrongfull conviction also hurt us It hurts the hole system the whole society.
      Even the deathpenelty hurt us even if the person are guilty.
      I mean what do we learn our kids? Revench isnt that some kind of lack of imagineation?
      That person can have family members they can have children and those children are of course innocent.
      If someone killed a family member of mine why Should I give that person Attention and time? It Doesnt make sense to me certanly not if I have children
      I prefer to give of my self to those I love and to those who need me and welcome me.

      I want to share the love I feel and bring light in to these situations where it can make a differense. What else matters …

      Pernilla Edberg

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