Lazcano joined the Mexican Army at the age of 17 and later ascended to the Grupo Aeromóvil de Fuerzas Especiales (GAFE), the Mexican Army special forces. During his tenure in the Mexican Army, Lazcano reportedly received military training from the Israeli Defense Forces and the United States Army, but eventually deserted in 1998, after eight years of service. Upon his desertion, he was recruited by the drug lord Osiel Cárdenas Guillén and Arturo Guzmán Decena with around 30 other soldiers to work as the enforcers of the Gulf Cartel, forming the paramilitary group known as Los Zetas. His torture methods earned him the nickname "El Verdugo" ('The Executioner'), particularly for killing his victims by feeding them to lions and tigers he kept in a ranch.
Lazcano died in a shootout with the Mexican Navy on 7 October 2012. According to news reports, "in an embarrassing twist"..."before the government could even begin to celebrate such an important victory in its battle against the drug cartels, officials learned that an armed gang had invaded a funeral home and snatched the body."