A man has been arrested after a horse died following a "brutal" attack in her paddock.
Owner Tracy Grantham said she found 17-year-old Sindy with a gaping wound to her neck and shoulder in her field in the Mendham area of Suffolk on Tuesday.
The injuries were so severe she had to be put down.
A 34-year-old man from the Norwich area was arrested on Saturday on suspicion of criminal damage and has been released under investigation.
Mrs Grantham, who bought the thoroughbred cross four years ago, has said: "To know that someone has done this to an innocent creature beggars belief.
"She didn't trust people - there was something in the past - but we taught her to trust people and that was her fate."
The horse failed to react when they they tried to stable her for the night and they "immediately knew something wasn't quite right".
"I assumed it was a horrific accident, but the vet said 'I think we need to contact police, this is not an injury the horse has done to herself'," Mrs Grantham said.
"She was given a heavy dose of painkillers but it was evident the extent of the injuries were irreparable."
Mrs Grantham's daughter, who was there, described the injuries as "brutal".
Suffolk Police is continuing to investigate the "disturbing" attack, which happened between 16:00 and 18:00 GMT.