Spanish police are investigating the discovery of decapitated and mutilated dolphins found on beaches, including one animal with a name carved into its flesh.
The gruesome discovery was made along the coast of Almería in the southern region of Andalusia.
Authorities said the cuts had definitely been made deliberately by a human as some of the injuries included carvings of initials and the name Juan.
The Guardia Civil has launched an investigation, saying there have been 'numerous' similar incidents and stating that the way the dolphins were decapitated suggests the individual responsible is someone with significant knowledge of marine life.
Photos released by the Guardia Civil show the severed head of one dolphin and the flank of another with the name Juan carved into its side in large letters.
Another image shows the decapitated body of a dolphin.
Among the decapitated dolphins found on Spanish beaches was one with the name Juan carved into its side
A Guardia Civil photo shows the decapitated head of a dolphin. The Guardia said numerous similar incidents have occurred in Almería
One of the mutilated dolphins was found on the Cala Príncipe beach in San José.
Animal welfare volunteers discovered the shocking scene and requested assistance with the stranding from the Ministry of Ecological Transition.
According to authorities, the way the animals were decapitated suggested the perpetrator had knowledge of marine life
The ministry determined that the damage to the dolphin's body was man-made.
The animal's head was later discovered on a nearby shoreline.
Spanish media reported that the mutilated mammal was a striped dolphin - a species that enjoys special protection under Spanish law.
Equinac - the animal rights group - posted a message to the perpetrator on its social media warning that their arrest was imminent.
'Bear in mind that Almería's Guardia Civil is conducting an investigation and they are very good,' it said.
The post also echoed the Guardia Civil's assertion that the person responsible had knowledge of the anatomy of dolphins.
'We know the cuts are being made by someone who has experience in dismembering these, or other, marine animals.'
'If you go on, we will too, until we catch you,' the group warned.