Threatening messages aimed at drug traffickers were found with the heads, which were covered with tape. The heads were discovered in individual coolers near the community of Ixtlahuacan del Rio.
Search for the bodies are on, according to a news released by the state prosecutor's office.
Investigators believe the victims were beheaded hours before police made the discovery.
Drug violence has claimed more than 7,200 lives since Jan 2008 as cartels battle each other and the govt for territory.