PLYMOUTH – Penobscot County Sheriff’s Deputy Sean McCue is investigating the possible drugging of three horses on the Clark Road.

The horse owner, who owns one of the pleasure horses and boards two others at her barn, reported Sunday evening that she found several fist-sized rocks in the horses’ stalls, rocks that were too large for the horses to have dragged in on their hooves, McCue said.

Upon closer investigation, the owner found several apples that had pills stuck in them, also in the horses’ stalls.

McCue said the pills were an ephedrine-based substance and were intended to either kill or sedate the animals.

“This is a very unique situation,” McCue said. “Someone was trying to drug her horses, for whatever reason.”

He said it is unclear whether the horses ingested any of the drugs, and the horse owner could not be reached for more information. The deputy did not know what type of horses they were.

McCue said the owner believes rocks were thrown at the horses, which are housed in stalls fairly close to the road.

The deputy said he is investigating problems that the owner recently had with a neighbor regarding the horses, but “all we have is a lot of speculation at this point.”