On August 23, Adventure Horse Trekking NZ Ltd director John Wall found one of his most valued horses shot dead in a paddock in Waihaorunga.
"I just went out to check, to get my cattle off the same block as my horses were on, and I found this little horse dead in the gully," Mr Wall said.
Thunder was found with grass still in his mouth and bullet wounds in his shoulders, Mr Wall said.
The horse, a 9-year-old half Shire station bred, 16.1hands high, was a valuable part of the tourist company and was often used to carry older and sometimes less experienced clients because "he was so trustworthy".
"He was the leader of our herd of horses, one of our top half-dozen most valuable horses to our business."
Mr Wall believed a hunter or hunters in the area mistook Thunder for a deer and shot him from Kaiwarua Rd.
He said the people responsible broke several laws, including not gaining permission to shoot on the property, and they had not clearly identified their target before shooting.
Mr Wall was disappointed no-one had approached the business or the police to claim responsibility.
Sergeant Kevin Reynolds, of Waimate, said if the shooting was an accident the people responsible should come forward to explain what happened.
People needed to be more careful about identifying targets.
"You shouldn’t be shooting horses."
• Crimestoppers on 0800 555-111.
