The federal Bureau of Land Management confirmed Monday that at least 73 wild horses were gunned down in an isolated central Nevada area.
BLM spokeswoman Maxine Shane added that another dozen animal carcasses have been found by investigators in the area, along with spent bullets and other physical evidence.
Shane said an exact count will not be known until investigators can check all the bones and carcasses spotted by a helicopter crew earlier. She added that a few of the remains may be of cows that died of natural causes.
More than 38,000 wild horses now run the open range in 10 Western states. Nevada's herds are the largest of any in the West, with estimates of up to 28,000 of the animals roaming the state.