December 28, 2014, dawned auspiciously cold and clear in southwestern Utah. Two hunters, Doug Blackburn and Gray Hansen, had risen before the sun to drive into the high plateau country of the remote Tushar Mountains, where they planned to hunt cougar. A fresh layer of snow had fallen overnight, and animal tracks stood out as legibly as sentences on a page. The air was still, meaning that scents would be easily picked up by the five hounds that waited, impatient, in the back of their pickup.

The hunters drove slowly through a steep valley. Blackburn, a barber, was stationed…