Rhona Margaret Duncan was a 16-year-old White female living in North Vancouver, British Columbia, when she was killed during the summer of 1976. Online accounts place the sequence of events on the night of July 16 and the early morning of July 17, rather than indicating that she died during the daytime on July 16. That evening, Rhona attended a birthday party on East Queens Avenue with her boyfriend, Shawn Mapoles, and a large group of teenagers.
What had been intended as a relatively small gathering grew to roughly 60 people, and police were reportedly called at about 1:00 a.m. as the party was being brought under control.
Rhona left the party with Shawn, her close friend Marion Bogues, and Marion's boyfriend, Owen Parry. The four walked through North Vancouver together before the two boys separated from them to head toward their own homes. Rhona and Marion continued walking until they reached Marion's home. After saying goodbye, Rhona began the final portion of the walk to her own house alone. One detailed account places this at approximately 2:45 a.m., with about five blocks remaining between her and home.
At approximately 3:00 a.m., a nearby resident heard what sounded like a man and woman arguing outside. Her husband went into the yard and called toward the source of the disturbance, asking what was happening. There was no response, and the argument suddenly stopped. The significance of what the neighbors had heard would only become apparent later that morning. By approximately 9:00 a.m., Rhona's partially clothed body was discovered in tall vegetation near a neighbor's garage, only a short distance from the safety of her own home. A post-mortem examination determined that she had been sexually assaulted and killed by manual strangulation.
The RCMP launched an extensive investigation, questioning Rhona's friends, acquaintances and others who had been at or connected to the party. Investigators administered polygraph examinations to a number of people and eventually compiled a list of 172 males that included friends, acquaintances, persons of interest and potential suspects. Shawn Mapoles received significant investigative attention early in the case, but he voluntarily underwent a polygraph examination and was later eliminated through DNA testing. No evidence ultimately connected him to the killing.
The case received an important forensic development more than two decades later. Evidence preserved from the original crime scene was examined as DNA technology became available, and investigators were able to develop a DNA profile attributed to Rhona's unidentified attacker. Police subsequently sought samples from men who had appeared in the original investigation. More than 170 individuals were reportedly tested, but none matched the crime-scene profile. The testing allowed investigators to eliminate several people who had once been considered higher-priority subjects. Other individuals on the original list had died by the time DNA testing became possible or could no longer be located.
Despite decades of interviews, polygraphs and DNA comparisons, investigators have not publicly identified the person whose DNA was recovered in connection with Rhona's killing. No one has been arrested or charged with her murder, and there has consequently been no criminal trial or conviction. The homicide remains an open North Vancouver cold case, with the preserved DNA evidence continuing to provide a potential means of identifying the killer if a future comparison produces a match.
