Who’s Killing Buck Birdsong’s Cows?

Interesting mystery, with no solution as yet:

Over the next four years, fifteen more of Buck’s calves would die. Investigators with the sheriff’s office, a Texas game warden, and even a special ranger with the Texas and Southwestern Cattle Raisers Association have worked the case, but so far, none have been able to identify any leads. The cause of death, however, is clear: the same toxic grain has been found inside each dead calf. Someone, it seems, is intentionally killing Buck Birdsong’s calves.