Police in North Wales are urging local farmers to be vigilant after 22 sheep were killed on a farm.
North Wales Police say the ewes and lambs died in a lambing shed in Llannefydd, Conwy county, at some point between 6.30pm on Monday and 8.30am on Tuesday.
Officers say there are no visible injuries such as bite marks on the animals.
The force’s working assumption is that a dog entered the shed and “panicked” the flock into a corner.
Police suspect the animals suffocated after they were kept there for some time.
While it is possible the dog responsible could be a working sheepdog, a spokesperson for the force said it could not substantiate this.
As the identity of the dog has not been established, police are concerned there may be further incidents.
Farmers in the Llannefydd area have been warned to keep a close eye on their sheep.