COUSHATTA, La. (AP) — Authorities are investigating the shooting death of on horse and the theft of others in Red River Parish.

Bobby Speed says he doesn't know why someone killed his 6-year-old son's horse, but he says the boy is heartbroken. Speed came home on July 11 after tending to a family emergency to find Last Chance, an American saddle bred horse, dead in the pasture.

The Shreveport Times reports ( ) that the River Parish sheriff's office and Louisiana Livestock Brand Commission are jointly investigating the horse's death, in addition to three horse thefts in the area.

Four Forks Shelter in Keithville, a horse rescue organization, learned about the death of Speed's horse and donated one to his son.