Police are searching for the culprit behind the decapitation of four lambs in the Forest of Dean, with farmers being urged to stay vigilant.
The shocking incident happened on a farm in Newent over the weekend, and police are appealing for information.
The carcasses had been removed and the heads left in situ in the field in Malswick, Gloucestershire Police said.
It is believed that the incident happened overnight between 8pm Friday 19 May and 5pm Saturday 20 May.
There were 16 sheep in the paddock on the farm, but the others have since been moved to a different location.
Police are investigating and asking for anyone who has information on what happened to come forward.
"If you see suspicious activity taking place and offenders are present or nearby, call police immediately on 999," the force said.
"Officers from the Rural Crime teams are now taking part in additional patrols and liaising with local farmers to raise awareness of this issue.
"Information can be provided to police online by completing the following form and quoting incident 331 of 20 May."
The latest figures show that the cost of rural crime rose over 40% in the first quarter of 2022 as thieves returned to the countryside - following falls in 2020 and 2021.