One morning in the fall of 1980, Rex Shaddox got a call from his supervisor at the Uvalde, Texas, office of Animal Damage Control. Shaddox had worked for Animal Damage Control, which was then a branch of the U.S. Fish and Wildlife Service, for seventeen months. His job was to trap and kill wild carnivores, coyotes in particular, that were said to prey on the flocks of local sheep ranchers.
The supervisor, Charles Brown, told Shaddox to meet with his fellow agents at the city dump outside town. “We’re gonna do some M-44 tests,” Brown said. “With dogs.” The M-44, a spring-loaded device that is planted in the ground and ejects sodium cyanide when set off, was among the weapons used by Animal Damage Control to kill coyotes.