Carol Murray, from Marykirk, took the difficult decision to have 17-year-old Saxo put down after finding him in a distressed condition in his field shelter near the village last Monday.

She said someone had got into his field to plait his mane, the latest in a series of incidents which has gone on over the last four or five years.

They began a year after she bought the white gelding from an animal sanctuary as a companion for her other horse. Although disturbed by the occurrences, she said Saxo had never been harmed physically but she became more concerned the longer they continued.

Ms Murray installed a CCTV camera in one of her field shelters and reported the matter to the police. She also asked around the village for information but enquiries with other horse owners in the area drew a blank.

She found Saxo in his shelter "shaking, sweating and distressed" when she went to give him his morning feed.

She said: "It happened sporadically, perhaps once every two to three weeks and then months might go past with nothing, but it was more concerning when they started going into his stable with him. I thought it might be kids but the fact he was difficult to handle maybe rules that out. It doesn't seem to have been happening to anyone else.

"When I saw him on Monday he was lying down and just didn't want to know. I got the vet out straight away. She didn't think they'd done anything physically to him but the stress had caused colic which we couldn't bring him back from and he had to be put down.

"The vet put the cause directly down to this happening. The back of my field shelter's been damaged so I hate to think what went on."

She added that she had "racked her brains" as to why Saxo had been targeted while her other horse had been ignored. She even considered that it might have had a ritual significance.

She said: "I just don't understand it. Someone must know something – maybe they saw someone coming home covered in mud as the field was very muddy. I'd even be prepared to offer a reward for any information."

Cases of mane plaiting, possibly linked to Pagan rituals, have been reported in other parts of the UK. In the south west of England 20 horses were targeted over a three-month period up to early December. A further 10 cases were reported in Sussex over a similar period of time.
Police in Dorset believe they might be related to knot magic, the practice of tying knots in cord or thread to help with spell-casting and prayer and several Pagan gods are linked directly with horses.
A Grampian Police spokesman confirmed the incident had been reported to the force.

He said: "We did get a complaint regarding this and enquiries are ongoing at the moment."

Anyone with information about the incident can contact Grampian Police on 0845 600 5700 or Crimestoppers anonymously on 0800 555 111.