The seven-year-old bloodhound Bruno was found dead on Friday. According to the tracking dog's trainer, Arcangelo Caressa, the cause of death is that he got food that someone had hidden nails inside.
In a post on social media, Caressa urges the police to "find the murderer" and he is also said to have assisted the police with information about two people he suspects.
Bruno has helped find nine people during his career as a tracking dog and the death has affected politicians at the top level.
Italy's Prime Minister Giorgia Meloni, who was photographed with the tracking dog after one of his rescue operations, calls the incident "unacceptable".
Italy has a new animal protection law that came into force on July 1 and means that anyone who abuses or kills an animal can get up to four years in prison and a fine of 60,000 euro.