One horse was killed and another seriously injured after being stabbed in a brutal attack.
Police said the animals were grazing in a field in Haltwhistle, Northumberland, when they were attacked sometime between 7pm on Friday July 8, and 10am on Saturday, July 9.
The horses were taken to a vet for treatment but one of the animals has since died from its injuries. The other animal is being monitored by vets as it recovers from the injuries and the owner has been left incredibly upset by the incident.
Police are carrying out a number of enquiries to try and locate those responsible and have now appealed for any witnesses to get in touch.
Anyone with information should call 101 and quote the reference 481 09/07/16. People can also contact Crimestoppers anonymously on 0800 555 111.