At least 45 lambs and sheep have been “professionally slaughtered” in fields in Northamptonshire, with several left butchered for farmers to discover.
In the past week there have been four brutal attacks, the incidents occurring within 30 miles of one another.
Police believe the spate of butchery began last Sunday when 14 lambs were killed between 4pm on Sunday and Monday afternoon.
The carcasses of 12 lambs were stolen, with the remains of two others left in the farmer’s field near West Haddon.
In the village of Whilton, near Daventry, 21 lambs were killed and then stolen at some point between the early hours of Tuesday morning and Wednesday morning.
The butchered remains of at least 10 sheep were later discovered on Saturday morning in a field in Kelmarsh, and in nearby Moulton a lamb was found tied up with the wire from an electric fence.
Northamptonshire police are now warning farmers to remove loose fencing or farm equipment and to watch out for suspicious activity.
Insp Scott Little said: “To have this many incidents in just a few days is extremely concerning and we are appealing for information from the rural community to help us catch those responsible.
“The lambs appear to have been professionally slaughtered and their carcasses have then been stolen.
“For farmers to find their animals have been killed and butchered like this is not only very upsetting, it also has financial repercussions.”
Police will visit farmers and other landowners over the next few days as part of their inquiries.
Little added: “If you suspect someone has attempted to target your animals or find that you’ve lost livestock in this way, please report it to the police immediately.”