Los Zetas Prison Escape On Sept. 17, 131 prisoners escaped the Cereso prison in Piedras Negras, Coahuila state, through one of the prison entrances and through a tunnel that the inmates dug. The prison held approximately 730 prisoners before the escape. According to Coahuila state authorities, Los Zetas planned the escape in order to refill their ranks with gunmen. The authorities presumably came to this conclusion during the investigation and following arrests, and several details of the escape seem to confirm this assessment. A responding SWAT team was ambushed en route to the prison from Zaragoza, Chihuahua state, and buses were stolen to transport the escaped prisoners, who were immediately armed. It is unclear whether responsibility lies with Los Zetas or with the dissident Los Zetas plaza boss Ivan "El Taliban" Velazquez Caballero .