Arrest could mean death knell for Los Zetas , ex-intelligence executive says . Los Zetas-Gulf Cartel split unleashed `` violence all over Northeast Mexico '' Death of U.S. agent , casino fire brought added U.S. , Mexican focus on group . Take the group 's leader , Miguel Angel Treviño Morales , aka `` El 40 '' or `` Z-40 , '' who was taken into custody this week during a Marine operation south of his hometown of Nuevo Laredo . Score: 6
Arrest could mean death knell for Los Zetas , ex-intelligence executive says . Los Zetas-Gulf Cartel split unleashed `` violence all over Northeast Mexico '' Death of U.S. agent , casino fire brought added U.S. , Mexican focus on group . Score: 6