The split of Los Zetas began in 2010 , when a regional leader of the organization disobeyed orders and killed 72 illegal immigrants and nearly 200 people in the northeastern Mexican city of San Fernando , Tamaulipas . In August 2011 , several low-level Zeta members went into a casino in northern Mexico and set the place on fire . In the attack , which was a retaliation for the owner 's failure to pay for " protection " , 52 people were killed . The massacre was among the deadliest in Mexico 's drug war and brought attention from the government . The mastermind of the attack turned out to be a mid-level leader who had carried out the attack without the approval of the top echelon . In mid-2012 , a regional cell disobeyed Morales ' commands and dumped 49 decapitated bodies on a roadside ; Morales had ordered his henchmen to abandon the bodies in a city 's main square and not outside the city limits
49 decapitated bodies
Cadereyta Jiménez massacre
Infighting in Los Zetas