An investigation was under way on Sunday after two horses were found dead in a field, police said.
The owners of the Shetland ponies made the discovery at 10.30am after they had gone to feed them at Carharrack, near Redruth, Cornwall.
Police said the investigation into the ponies' deaths would focus on how they died but it was believed to be as a result of a deliberate attack.
But the attack was not being linked to an earlier incident in nearby Stithians in January when a two-year-old colt, called Erik, died after being horrifically mutilated.
In that attack police were considering whether the stallion's death was part of a ritual killing.
Detective Inspector Pete Simms, of Devon and Cornwall Police, said: "It would appear that the ponies were killed in a deliberate act. However, whilst we are keeping an open mind, we do not believe that there is any link with the recent horse death at Stithians.
"We would appeal to all members of the local community and, in particular, horse owners for information about this incident. It is important that they remain vigilant and report any suspicious incident or activity to the police."