Complex sentence: The victims are believed to be members of the Gulf Cartel, a rival drug trafficking organization and the former employers of Los Zetas, but officials have not ruled out the possibility that the victims were U.S.-bound migrants.
Split into simpler sentences: The victims are believed to be members of the Gulf Cartel, a rival drug trafficking organization and the former employers of Los Zetas. But officials have not ruled out the possibility that the victims were U.S.-bound migrants.