Another head has been found in the city of Colima in the western part of Mexico, media reported on Tuesday.
At the crime scene in Tlaxcala, a pamphlet was also found that accused criminal gangs in the state of spreading violence and plundering fuel as well as drug trafficking.
Violent showdowns between criminal gangs have paralyzed large parts of northern Mexico, often with brutal attacks where heads are cut off from the victims. In the state of Sinaloa, twenty bodies were found, five of them headless, at the end of June.
Similar brutal violent acts have previously been more unusual in the states of Tlaxcala and Puebla.
Around 480,000 have been confirmed dead in drug-related violence since the unrest intensified in 2006. Another approximately 130,000 people have been reported missing.
