Police have issued a public health warning following the theft of sheep which had undergone worming treatment.
Five sheep have been stolen on two separate occasions from land near Cottingham, Northamptonshire.
Five of these sheep turned up having been killed, skinned and the meat taken in a manner showing it was clear they were killed for their meat.
Police have issued a warning to the public and butchers to be vigilant as the meat is likely to be contaminated.
The sheep in question were stolen the day after they were given Noromectin, a drug used to treat worms in sheep.
The safety advice is the sheep must not be slaughtered for human consumption until 42 days after the last treatment. While the risk is not great, the company which produces the drug says it has the potential to cause nausea, vomiting and diarrhoea.
A police spokesman said: "We’d ask the public to be very vigilant of people selling meat in the area, in particular local butchers who might be approached."
The news comes as a Cumbrian farmer dyed his flock of sheep orange to clamp down on sheep rustling issues.
Farmer Pip Simpson said in the last few years he has had an excess of 300 sheep ’pinched’ from his farm.