Six severed human heads were found on a road connecting the Mexican states of Puebla and Tlaxcala on Tuesday, Aug. 19. A person called 911 after seeing a head on the side of the road.

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.