A horse found dead at the Salt River Recreation Area in Arizona is now the subject of an animal cruelty investigation by the Maricopa County Sheriff’s Office (MCSO).

Simone Netherlands, president of the Salt River Wild Horse Management Group, said a caller to the group’s hotline reported seeing a horse’s remains on Oct. 1 at the recreation area near Coon Bluff. The animal was part of the Salt River wild horse herd, Netherlands said.

After further investigation, the organization determined that the 12-year-old mare had sustained a single gunshot wound.

“After we conducted our own investigation, we contacted the MCSO,” Netherlands said