According to the another Teck interview with Whatcom native William Utter, Alice (Bill’s longtime Indian wife) sewed Bill’s clothes from Hudson’s Bay blankets, and sometimes he reverted to Indian fashion and wrapped himself only in blankets. That affectation from his early days with Indian tribes may have been the basis for his name [William ‘Blanket Bill’ Jarman] and the kidnapping tale may have been spun from it.
A stratigraphic-geochemical study of the Troutdale Formation and Sandy River Mudstone in the Portland basin and lower Columbia River Gorge (pdx.edu)