Real Names: Stephen Harkins and Ruth Cooper
Nicknames: No known nicknames
Location: South Pierce, Washington
Date: August 11, 1985
Details: On August 11, 1985, 27-year-old Stephen Harkins and his 42-year-old girlfriend, Ruth Cooper, vanished after leaving a wedding reception in Tacoma, Washington, and arriving at a forest in South Pierce County to go camping. Four days later, he was found murdered; shot to death in his sleeping bag along with his dog. However, it would be two months before her body would be found, near a dead-end road with a tube sock tied around her neck. She had been decapitated and her head was found some distance away. Authorities believe that their murders were connected to the murder of Diana Robertson and the disappearance of her boyfriend, Mike Riemer. In December 1985, they went with their 3-year-old daughter, Crystal, to look for a Christmas tree. That afternoon, Crystal was found wandering around a department store without her parents. She was later identified after her photo was placed in the newspaper and her maternal grandmother recognized her. Mike and Diana had vanished without a trace, and all Crystal could tell police is that "Mommy is in the trees". Two months later, Diana's body was found deep in the forest around Elbe, Washington. She had been stabbed seventeen times and a tube sock was tied around her neck, there was no sign of Mike. His truck, which was nearby, had blood stains on the front seat and a note on the dashboard that read, "I love you, Diana." Although her mother believed that it was his handwriting, it could not be confirmed. There were several connections between the two cases. First, they were camping in the same area where Mike set his traps. Both Ruth and Diane had been killed with the tube sock tied in the same way. Police considered two theories; the first was that an unknown serial killer had killed both couples, and then hid Mike's body. The other theory was that Mike himself was the serial killer. He apparently had a history of domestic violence, and this, along with other evidence, was enough for police to issue a warrant for his arrest. Police have never been able to determine if he is alive or dead, or if he was the killer or a victim.
Suspects: Mike Riemer
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 found that was identified as Mike's. The cases still remain unsolved, however. Police have since ruled him out as a suspect in the double murder, and authorities now believe that an unknown serial killer may be responsible for the Harkins/Cooper and Robertson/Riemer murders. An unidentified man was searching for Stephen Harkins on the night of his death, wanting to settle a dispute about damage to his motorcycle. It's a possible suspect in the case. New DNA testing is being done on evidence in the case, but it remains unsolved.