According to Mexican authorities, the Zetas have become the biggest drug trafficking organization in Mexico. A recent report from Stratfor, based on data from Mexico's attorney general's office, says the group now operates in 17 states, surpassing the geographical sway of the once-dominant Sinaloa Federation.
Some say Mexico needs to learn from its experience in Michoacán by recognizing it has no reliable partners among state and local forces, who are often in cahoots with drug gangs.
Brutality and shock tactics are a way for new gangs to assert themselves, and could be rising because of the splintering of larger transnational criminal organizations.
Heriberto Lazcano, a Zetas drug cartel leader, was killed in a northern Mexico gunfight on Sunday, according to the Mexican Navy. If true, it could be a major drug war victory for Mexico.
The Mexican Navy reports there are 'strong indications' that marines killed Zetas top man Heriberto Lazcano. Could this mean the end for the Zetas, or trigger more violence?