A farmer has found six dead sheep with broken necks and eyeballs removed.
Daniel Alford, of Devon, found four corpses laid out in a square. Two others were near stones and apparently arranged to make a pagan symbol.
Mr Alford said he believed occultists could be responsible. Devon and Cornwall Police said the incident is being investigated.
Mr Alford found seven sheep killed and left in a circle less than half a mile away near Tavistock in January.
The six dead animals were discovered as he did his rounds on Sunday morning after a clear full moon on Saturday night, he said.
Two of the sheep were killed on a remote part of Dartmoor at least half a mile from any road.
Mr Alford said: "This was a sacrifice - they had their necks broken.
"Initially when you think of sacrifices you think sharp knives and slit throats. That wasn't the case here.
"If they had killed them and taken them away, I would have accepted it more. Just to outright kill them and leave them is such a waste."
Mr Alford, from Sampford Spiney, near Tavistock, said the sheep were wild moorland animals and would have been difficult to catch without a net.
He added: "You wouldn't just get kids catching sheep like that. Someone's got to know what they're on about."