Olson was an informer on the outside of the prison walls and a snitch on the inside. While in the Penthouse, he enticed rapist-murderer Gary Francis Marcoux to discuss the murder of a little girl, in written form, and eventually used it as evidence against him in a court of law. These letters and maps that were passed between Olson and Marcoux not only helped convict Marcoux, but taught Olson his own future method of operation.
Marcoux dumped the body of nine-year-old Jeanna Doove at Weaver Lake, a popular camping area in the coastal mountains overlooking the valley east of Vancouver. The letters between them described in graphic detail how Marcoux lured the little girl to his car from her trailer court in Mission, some 50 yards from the Genesis Halfway House where he was living, bought her ice cream, then raped, strangled, and mutilated her, leaving her tied to a large tree near Weaver Lake. He also described a nearby back road that connected to Pemberton and Whistler. He even provided maps on how to drive to the murder site. She was found on the July 1 Canadian holiday.
By January 1981, especially since Olsons release on mandatory supervision, a more sinister and frightening persona had emerged. He had charges in different jurisdictions. The Squamish charges included rape, buggery, and gross indecency; the Richmond charges consisted of buggery and indecent assault on a male; a May incident at Agassiz with a young girl; and a July indecent assault of another young girl.
Early in Olsons criminal career, after he had escaped from Shaughnessy Hospital, his parents made an appeal to the media: Id like him to give himself up, said Olson Sr., But he knows what hes facing. He might have to serve 10 years. If he doesnt give himself up, I hope they get him before he does something really bad. Hes done bad enough now.
Hes a coward by himself, said his mother, knowing her Clifford to be a show off. Hes got to have a partner. Clifford never does anything alone.
In retrospect, Olsons mother was partially right. Olson in his prison partnership with Marcoux had developed a taste and a methodology for killing. Olson bragged in his unpublished manuscript that he started as a petty thief and graduated from the Canadian prison system as a prolific killer.