More than 40 sheep have been killed and a further 50 injured in attacks in Lancashire.
In the first incident, on Wednesday night, 29 sheep were found dead in land off Preston New Road, Fylde. About 30 others were badly injured.
Another 12 were found dead in Mythop Hall Farm in Mythop Road, Fylde, on Thursday lunch time. Twenty others had bite injuries.
Police said the injuries were consistent with a dog attack.
Ch Insp Sue Cawley, of Lancashire Police, said: "This is a highly unusual occurrence and I am appealing for anyone who may have seen any suspicious activity in the area to come forward and contact police.
"The injuries sustained by these sheep are consistent with being attacked by a large dog but we are keeping an open mind."
She added: "In addition to the horrific injuries suffered by the sheep, it is currently lambing season so the majority of the sheep were pregnant."
"This is a devastating loss to the farmers involved whose livelihoods will be affected by these deaths and we need the public's help to establish what has happened."
Ch Insp Cawley urged anyone in the area to remain vigilant and to report any suspicious activity.