Complex sentence: He joined the Mexican Army in 1993, but deserted six years later in the summer of 1999, and was recruited by the Gulf Cartel to work as an enforcer for the drug trafficking organization's new muscle, Los Zetas.
Split into simpler sentences: He joined the Mexican Army in 1993, but deserted six years later in June 1999. He was later recruited by the Gulf Cartel to work as an enforcer for the drug trafficking organization's new muscle, Los Zetas.