The State Attorney General’s Office will continue the relevant investigations to clarify what happened and hold accountable whoever is found responsible,” the prosecutor’s

Messages are often left on victims' bodies by cartels seeking to threaten their rivals or punish behavior they claim violates their rules.

Six severed heads have been found on a road in central Mexico, in an area not normally associated with cartel violence. Local authorities made the discovery early on Tuesday morning on a route that links the broadly peaceful states of Puebla and Tlaxcala.