Owners in west Dorset and the surrounding counties had believed that thieves plaited the manes of the beasts to identify which ones to steal when they returned at night.
But police officers investigating the incidents said there had been no thefts, and instead their enquiries led to the world of pagan ritual.
It is now believed that the practice is a part of white witch "knot magick" that is used when a spell is cast.
It seems those responsible to go extreme lengths at night to carry out their plaiting as horses have had their manes knotted on nights of high wind and rain.
And some of those targeted have been in fields surrounded by electric fences, miles from anywhere.
It is not known exactly how many horses have been targeted but at least a dozen are known to have had the treatment.