Prison staff have filed a police report after a dead frog was thrown over a prison wall with a mobile phone stuffed inside it in a macabre smuggling attempt.

After hearing a commotion coming from outside, a prison guard went to the scene and found the dead frog on the roof of a building adjoining the Montes Claros I Penitentiary in the Brazilian city of Montes Claros on Tuesday, 21st September.

Upon inspecting the dead amphibian, the officer noticed it had a suspiciously square shape, so it was cut open with a knife and a mobile phone was found stuffed inside it.

Staff at the prison noted that the animal was missing its legs, and they believe it had been killed shortly before it was thrown over the prison wall.

The mobile phone, which is a smartphone, was handed over to the police, who will investigate the incident. The prison has also launched its own internal inquiry into the incident.

At the time of reporting, it was not known which inmate the mobile phone was destined for, nor the identities of the people who threw it over the prison wall.

Public safety regional director Antonio Jose Costa said in a statement: “We work daily to prevent these objects from entering our units. We have teams prepared to act and increasingly prevent the presence of prohibited materials.”