Who is El Mencho? Inside the rise of CJNG’s fallen kingpin and the cartel he built

Ruben "Nemesio" Oseguera Cervantes, known as "El Mencho," the powerful leader of the Mexican Jalisco New Generation Cartel (CJNG) who rose to prominence after the fall of Joaquin "El Chapo" Guzman, the former head of the rival Sinaloa Cartel, was killed Sunday in a Mexican military operation, authorities said.

Under Oseguera’s leadership, CJNG expanded aggressively across Mexico, battling Sinaloa for control of key trafficking corridors into the United States and cementing its status as...