El Chapo’s Cartel: Killings, Jealousy and Shifting Alliances - The New York Times

To fill the vacuum, Vincente Carrillo Fuentes was promoted to run his brother's business and soon found himself in a power struggle with Mr. Guzmán, a witness said this week. According to the witness, Tirso Martínez Sanchez, Mr. Guzmán sought to control a lucrative train route that moved cocaine across the border to Los Angeles, Chicago and New York. The train route regularly earned the cartel's leaders hundreds of millions of dollars. But Mr. Guzmán wanted to cut Mr. Carrillo Fuentes out of the profits, Mr. Martínez said.

Complicating matters, Mr. Carrillo Fuentes's other brother, Rodolfo, soon struck up a partnership with a rival cartel, the Zetas, which mostly operated along the Gulf of Mexico. Initially, witnesses have said, the Zetas and the Sinaloa traffickers worked well together. But their relationship soured in 2002, when a high-ranking Sinaloan gunman killed the brother of a top Zetas leader and then sought refuge with Mr. Guzmán's allies, the Beltrán-Leyva brothers.

Though the Zetas wanted the assassin, prosecutors said, the Beltrán-Leyva brothers refused to hand him over. Another war eventually broke out, pitting Mr. Guzmán and the Beltrán-Leyvas against the Zetas and the Carrillo Fuentes brothers.

Amid the war, witnesses have said, Mr. Guzmán dispatched assassins to execute Rodolfo Carrillo Fuentes. Indeed, in 2004, Mr. Carrillo Fuentes and his wife were gunned down as they exited a movie theater in Culiacán.

That same year, the cartel's structure changed again as Vincente Carrillo Fuentes quit the group, leaving Mr. Guzmán and his last initial partner, Ismael Zambada, in charge. At the time, prosecutors said, the Beltrán-Leyva brothers also rose in the ranks — though that did not last long.

By 2007, in fact, Mr. Guzmán was warring with the Beltrán-Leyva brothers, according to Jesus Zambada García. Though the origins of the war remain somewhat obscure, Mr. Zambada said it erupted partly over the brothers' role in the seizure of an enormous shipment of cocaine that was coming out of Panama.

Mr. Guzmán's fight with the Beltrán-Leyva brothers was extremely violent, Mr. Zambada said, leading to the deaths of hundreds of people. It was also extremely complicated. The Beltrán-Leyvas, for example, struck up an alliance of convenience with the Zetas. That was awkward given that their onetime enemy, Vincente Carrillo Fuentes, was still closely connected to the group.