Unsolved Mysteries Wiki

Ruth Cooper and Stephen Harkins

Real Names: Stephen Alexander Harkins and Ruth Eleanor Cooper
Nicknames: Steve (Stephen)
Location: Pierce County, Washington
Date: August 10, 1985


Details: Twenty-seven-year-old Stephen Harkins and his forty-two-year-old girlfriend Ruth Cooper worked together at a vocational school in Tacoma, Washington. She was the single mother of four children. They had lived together for two years. On the night of August 10, 1985, they went to a friend's wedding reception in Tacoma. After leaving there, they went camping in a forest near Tule Lake in southern Pierce County. Four days later, on August 14, he was found shot to death in his sleeping bag. Their dog was found shot to death nearby. Two months later, on October 26, her body was found near a dead-end road 1.5 miles away. She had been decapitated and her head was found about fifty feet away. She had been shot in the abdomen. A tube sock was found tied around her neck. Authorities believe that their murders were connected to the murder of Diana Robertson and the disappearance of her boyfriend, Mike Riemer. She was found in the same woods as Stephen and Ruth.
On the morning of December 12, 1985, Diana, Mike, and their three-year-old daughter Crystal into the woods near Tacoma, Washington to look for a Christmas tree. Mike, a trapper, also planned to check his animal traps in the area. Later that afternoon, Crystal was discovered wandering around a Tacoma department store without her parents. The store employees tried to find her parents, but were unsuccessful. After being checked at a local hospital, she was sent to a temporary foster home. Three days later, she was identified after her photo was shown during a news broadcast and her maternal grandmother Louise recognized her. She was then sent to live with her.
Mike and Diana had vanished without a trace; all Crystal could tell police is that "Mommy is in the trees". That weekend, an extensive search began for the couple. Mike's friends searched both the ground and the air for them, focusing on the areas where he set his traps. However, no trace of them was found. Two months later, Diana's body was found deep in the forest around Elbe, Washington. She had been stabbed seventeen times and had a tube sock tied around her neck. There was no sign of Mike at the scene.
Mike's family and friends believed that he was also killed. They believe his body was dumped nearby. However, other evidence at the scene seemed to point to him being involved. His truck, which was abandoned next to Diana's body, had blood stains on the front seat and note on the dashboard that read, "I love you, Diana." Although her mother believed that it was his handwriting, it could not be confirmed by the FBI laboratory. Tests on the blood confirmed that it was human; however, the blood type could not be determined.
Police believed that Diana and Mike's cases were related to Stephen and Ruth's. They were camping in the same area where Mike set his traps, just fifteen miles from where Diana's body was found. Both Ruth and Diana had been killed with the tube sock tied in the same knot.
Two theories emerged surrounding the cases. One was that an unknown serial killer had killed both couples and hidden Mike's body. The other was that Mike himself was the serial killer. He apparently had a history of domestic violence. According to friends and family, she was frequently beaten by him. A few weeks before her murder, Diana secured a court order, keeping Mike from seeing her. However, as Christmas approached, the couple reconciled.
Diana allegedly told her mother that Mike had threatened to kill her and that he would get away with it. However, his family and friends are convinced that he is innocent. Although they admit he had a temper, they do not believe that he would be capable of murder. Because of the cold temperatures, his father does not believe that Mike would leave his coat behind in the truck. He believes that Mike was killed first.
The circumstantial evidence was enough for police to issue a warrant for his arrest. However, police have been unable to prove if he is alive or dead. Stephen, Ruth, and Diana's murders remain unsolved.
Suspects: Mike Riemer is considered a possible suspect in Stephen and Ruth's murders, due to the similarities between the two cases.
Shortly after Stephen and Ruth left the wedding reception on the night of the murders, a man arrived at the reception looking for Stephen. He told guests that he wanted to settle a dispute over damage that occurred to Stephen's motorcycle. It is not known if the man is considered a suspect in the case.
Investigators also looked into the possibility that their murders were connected with the murders of Jay Cook and Tanya Van Cuylenborg in 1987, Robert and Dagmar Linton in 1986, and Kim Lavine and Edward Smith in 1985.
Extra Notes: This case first aired on the September 6, 1989 episode.
Results: Unresolved. In March 2011, a skull was found one mile from where Diana's body was discovered. It was identified as Mike's. The cases still remain unsolved, however. According to some sources, police have since ruled him out as a suspect in the double murder, instead believing that an unknown serial killer may be responsible for the murders. In November 2011, new DNA testing was conducted on evidence in the case, but it is not known if anything came from it.
Kim and Edward's case was solved in 1989 when a fingerprint on their car was matched to Billy Ray Ballard. He was later convicted of their murders and sentenced to life in prison. Robert and Dagmar's case was solved in 1990 when items bought with their stolen credit card were found in the storage shed of serial killer Charles T. Sinclair. He died while awaiting trial on murder charges in 1990. Jay and Tanya's case was solved in 2018 when DNA from the crime scene was matched to William Earl Talbot. He was later convicted of the murders and sentenced to life in prison. It is not known if Ballard, Sinclair, or Talbot are considered suspects in this case.