Known as “The Tube Sock Killings,” the Mineral, Washington murders were a series of brutal, unsolved homicides that took place in the rural areas of Lewis and Pierce County, Washington, in 1985.
The cases shocked the small, close-knit community and have remained one of Washington’s most notorious cold cases.
The First Victims: Harkins and Cooper
On August 10, 1985, Steven Harkins, 27, and his girlfriend, Ruth Cooper, 42, left their Tacoma, Washington, home for a weekend camping trip at Tule Lake in Pierce County. When they failed to return to work on Monday, their families reported them missing.
Four days later, on August 14, hikers discovered Harkins’ body near a remote campsite. He had been shot in the head while still in his sleeping bag. Nearby, their dog was also found shot to death. Initially, law enforcement suspected a connection to the unsolved murders of Edward Smith and Kimberly Diane La Vine, a couple found murdered near the Columbia River in March 1985.
On October 26, Cooper’s skull was discovered at the dead-end of Eighth Avenue South, approximately 1.5 miles from where Harkins’ body had been found. Two days later, her body was located 50 feet from her skull, along with her purse. A tube sock was tied around her neck, and the autopsy revealed she had died from “homicidal violence.”
Riemer and Robertson: A Gruesome Discovery
On December 12, 1985, Mike Riemer, 36, his girlfriend, Diana Robertson, 21, and their two-year-old daughter, Crystal Robertson, left their home in Tacoma, Washington, to find a Christmas tree in Pierce County. Later that evening, customers at a Kmart store in Spanaway, about 30 miles north of their last known location, found Crystal wandering alone at the store entrance.
When asked about her mother, Crystal reportedly said, “Mommy is in the trees.” She was too young to provide additional information. Crystal’s photograph was broadcast on local news, leading her maternal grandmother to identify her and take her into temporary custody.
Despite police searches, Riemer and Robertson were nowhere to be found. It wasn’t until February 18, 1986, that Robertson’s body was discovered by a motorist near a logging road off Washington State Route 7, south of Elbe, Washington. Like Cooper, Robertson had a tube sock tied around her neck, and an autopsy later revealed that she had been stabbed seventeen times.
Riemer’s 1982 Plymouth pickup truck was found near Robertson’s body with a note on the dashboard reading, “I love you, Diana.” Riemer’s handwriting was confirmed by Robertson’s mother. Bloodstains were found in the truck, but Riemer was nowhere to be found. Police suspected Riemer in Robertson’s murder, considering his recent domestic assault charge against her. However, they lacked a clear motive and evidence to confirm his guilt.
Potential Connections and Theories
Due to similarities between the cases, investigators speculated that Riemer could have been involved in both the Harkins/Cooper and Robertson cases, especially since both female victims were found with tube socks tied around their necks. However, it was also suggested that Riemer might have been a victim himself.
Another theory proposed that an unknown assailant had abducted Crystal and dropped her at the Kmart, driving the 45-minute distance with the child in tow after possibly killing her parents.
Decades Later: A New Discovery
In March 2011, a hiker discovered a human skull off State Route 7, near where Robertson’s body was found. DNA analysis confirmed it belonged to Mike Riemer, suggesting he was also a victim, thus ruling him out as the killer. The exact circumstances of his death remain unknown, leaving the “Tube Sock Killings” an unsolved mystery.
Unsolved Mystery
The Mineral, Washington murders continue to puzzle investigators and haunt the region. The unresolved details leave lingering questions: Who was responsible for these brutal murders? How did Crystal end up at the Kmart, and what might she have witnessed? Over three decades later, the “Tube Sock Killings” stand as one of the most tragic unsolved cases in Washington’s history.