The Tube Sock Killings: A Cold Case in the Shadow of Mount Rainier
Overview
In 1985, a series of brutal and still-unsolved murders cast a long shadow over the remote, wooded areas near Mineral, Washington. In two separate incidents, two couples were attacked, leaving four people dead and a community gripped by fear. The cases, dubbed the "Tube Sock Killings" by the media, are linked by geography and a bizarre piece of evidence: the use of a tube sock in the commission of the crimes against the female victims. For decades, the identity of the killer has remained a mystery, complicated by a long-time person of interest who was later reclassified as a probable victim. The slayings were featured on the television show *Unsolved Mysteries* in 1989, bringing national attention to the case, but the passage of time has yet to yield a definitive answer.
The First Murders: Steven Harkins and Ruth Cooper
On Saturday, August 10, 1985, Steven H. Harkins, 27, and his girlfriend, Ruth Cooper, 42, left their homes in Tacoma for a weekend camping trip. The couple, who worked together at a vocational school, set up their campsite near the scenic Tule Lake in Pierce County. When neither returned to work on Monday, their families reported them missing.
A search began, and on August 14, hikers discovered a grim scene at a remote campsite. Steven Harkins was found dead inside his sleeping bag, having been shot in the head, suggesting he was killed as he slept. The couple's dog had also been shot and killed nearby. There was no sign of Ruth Cooper, leading investigators to initially believe she had been abducted.
The search for Cooper continued for more than two months. On October 26, 1985, hunters discovered a human skull near Harts Lake, about a mile and a half from where Harkins' body was found. Dental records confirmed the skull belonged to Ruth Cooper. Two days later, the rest of her remains and her purse were located about 50 feet away. An autopsy determined she had died from a gunshot wound to the abdomen. A disturbing and significant piece of evidence was found with her body: a tube sock had been tied around her neck.
The Second Murders: Mike Riemer and Diana Robertson
Four months after the first bodies were discovered, another couple from the Tacoma area vanished. On December 12, 1985, Michael "Mike" Riemer Jr., 36, his girlfriend, Diana M. Robertson, 21, and their two-year-old daughter, Crystal, drove into the woods of rural Pierce County. Riemer, an avid outdoorsman and animal trapper, planned to check his trap lines and find a Christmas tree with his family.
Later that day, shoppers at a Kmart in Spanaway, about 30 miles north of the wooded area, found little Crystal wandering alone outside the store. When questioned, the toddler could only say that her "mommy was in the trees." Two days later, her grandmother saw her picture on a news broadcast and the child was identified. An intensive search was immediately launched for her missing parents.
For two months, search parties scoured the dense forests, hampered by heavy winter snowfall. On February 18, 1986, a person walking their dog discovered Diana Robertson's body off a remote logging road near Elbe, not far from Mineral. She had been stabbed 17 times. Like Ruth Cooper, she had a tube sock tied around her neck. Nearby was Riemer's red Plymouth pickup truck. Inside, on the dashboard, was a manila envelope with the words "I love you, Diana" written on it. Robertson's mother believed the handwriting was Riemer's.
The Victims
- Steven H. Harkins, 27 — A resident of Tacoma, he was on a camping trip with his girlfriend when he was shot and killed in his sleep on August 10, 1985. He and Ruth Cooper worked together at a vocational school.
- Ruth Cooper, 42 — A mother of five from Tacoma, she was camping with her boyfriend, Steven Harkins. After being missing for over two months, her remains were found on October 26, 1985. She had been shot, and a tube sock was tied around her neck.
- Diana M. Robertson, 21 — She disappeared on December 12, 1985, while on an outing to find a Christmas tree with her boyfriend and their young daughter. Her body was found two months later; she had been stabbed 17 times.
- Michael Lloyd Riemer Jr., 36 — An animal trapper and roofer, he vanished on the same day as his girlfriend, Diana Robertson. Initially considered a suspect, his partial remains were discovered in 2011, leading police to believe he was the fourth victim.
Investigation and a Startling Twist
The discovery of Diana Robertson's body with a tube sock around her neck immediately linked her murder to that of Ruth Cooper. The knots used on both socks were found to be identical. Investigators were faced with two primary theories. The first was that a serial killer was responsible for all four murders, having killed Riemer and hidden his body. The second, and for a long time the prevailing theory, was that Mike Riemer was the killer.
Suspicion fell heavily on Riemer. He had a history of domestic violence against Robertson, who had even sought a restraining order against him just two months before their disappearance, though they had since reconciled. Riemer was known to carry a .22-caliber handgun, the same caliber used to kill Harkins and Cooper. His knowledge of the remote woods where both couples were killed, due to his trapping activities, also made him a person of interest. The note found in his truck seemed to some like a final, remorseful message. For years, the case stalled with Riemer as the primary suspect, a fugitive from justice.
This theory was shattered in March 2011. A hiker exploring the woods near Mineral, about a mile from where Diana Robertson's body had been found, discovered a partial human skull. A tree was found growing through it, indicating it had been there for a very long time. Dental records confirmed the skull belonged to Mike Riemer. The discovery led Lewis County investigators to re-evaluate the entire case. While a definitive cause of death could not be determined from the partial remains, authorities were able to rule out a gunshot wound to the head. With this discovery, the belief shifted: Mike Riemer was not the killer, but the final victim.
Trial and Sentence
The Tube Sock Killings remain unsolved, and no one has ever been charged or brought to trial for the murders of Steven Harkins, Ruth Cooper, Diana Robertson, and Mike Riemer. The case is cold, though Lewis County detectives have stated it remains open. In recent years, they have hoped that advances in DNA technology might provide new leads from evidence collected at the scenes.
Aftermath and Legacy
The murders left a lasting scar on the small communities of Lewis and Pierce counties, quiet areas unaccustomed to such violent crime. The randomness of the attacks—targeting couples enjoying the outdoors—created a sense of vulnerability and fear that lingered for years. For the families of the four victims, the lack of answers has meant decades of unresolved grief. The case stands as one of Washington state's most haunting and perplexing cold cases, a dark mystery set against the backdrop of the Pacific Northwest's dense and unforgiving forests. The identity of the person or persons who committed these brutal acts remains, for now, known only to the silent woods.
