SALT RIVER, Ariz. - Sheriff Joe Arpaio's mounted posse began the search Tuesday morning for two horses shot on Friday in the Tonto National Forrest.

The two were a part of a band found near the Salt River.

"It's just so senseless," said Simone Netherlands, president of the Salt River Wild Horse Management Group. "We hope to get the son of a gun.

"This is a crime that goes beyond animal cruelty," said Arpaio. "Killing an innocent horse is as dangerous as it is disturbing. What else is this person capable of doing? We need to end this senseless slaughter of wild horses."

PREVIOUSLY: Baby horse killed, mutilated along Salt River

The suspect is believed to be a male, wearing black shorts or underwear and dark green shirt. Witnesses saw at least two other persons with the suspect at the time of the shooting. There are no descriptions of these two additional persons.

There is a $3500 reward being offered to anyone with information leading to the arrest of the suspect.