Peruvian authorities are investigating the killing of five penguins found dead at a centre for endangered species.
The remains of the rare Humboldt penguins - two adults and three pups - were scattered in two pools of water.
Prosecutor Karin Padilla told reporters the youngest of the pups was just eight months old and that the carcasses showed their throats had been slashed.
The killings reduced the number of Humboldt penguins at the rescue and breeding centre in Puerto Eten, on Peru's northern coast, to 16.
Humboldt penguins are a species of flightless birds that breed along the Chilean and Peruvian coasts, where they are believed to number no more than 50,000.
Each year, hundreds of these penguins get caught in fishing nets.
They are also threatened by the El Nino climate phenomenon, which occurs every two to seven years when the prevailing trade winds that circulate surface water in the tropical Pacific start to weaken.