Animal welfare authorities in Colorado hope the offer of a cash reward will lead them to whomever abandoned six horses in Costailla County last month.

Aime Cavarra, spokesperson for the Colorado Humane Society said that on May 22 a palomino mare, sorrel filly, bay filly, brown colt, bay colt, and gray colt were discovered in an open range near San Luis, Colo. On May 23 Costilla County Sheriff’s Department and Colorado Humane Society personnel removed the animals to the Harmony Equine Center in Franktown, Colo. All the animals were malnourished. One mare was humanely euthanized due to her poor condition, Cavarra said. The remaining animals are under rehabilitative care.

"These horses were just dumped on the open range and left for dead," Cavarra said.

The Costilla County Sheriff’s Office is investigating the incident. The Colorado Humane Society is assisting in the investigations, Cavarra said