It was in August 1979, while searching for arrowheads inside Idaho’s Civil Defense Caves – ancient lava tubes running from Yellowstone National Park, partly repurposed as a cavernous fallout shelter during the Cold War – that one unfortunate family found it: a human torso in a hessian sack, buried 20cm beneath the sediment. The identity of the deceased – whose other body parts were missing – and how they ended up in a cave just east of Dubois was debated from the beginning.