Borderland Beat, for perfectly understandable reasons, is being quite oblique these days, but I think the gist of this is that the Zetas wanted to get rid of a troublesome subordinate by hiring a contractor to murder and dump 49 people on his plaza on Mothers Day, thereby stimulating a fuss leading to his arrest. Obviously, content warning.
UPDATE: OK, here's an overview from the New York Times Magazine/Cartel leader level, where everything is kind of cool. The rise of Chapo Guzman:
But Chapo’s greatest contribution to the evolving tradecraft of drug trafficking was one of those innovations that seem so logical in hindsight it’s a wonder nobody thought of it before: a tunnel. In the late 1980s, Chapo hired an architect to design an underground passageway from Mexico to the United States. What appeared to be a water faucet outside the home of a cartel attorney in the border town of Agua Prieta was in fact a secret lever that, when twisted, activated a hydraulic system that opened a hidden trapdoor underneath a pool table inside the house. The passage ran more than 200 feet, directly beneath the fortifications along the border, and emerged inside a warehouse the cartel owned in Douglas, Ariz. Chapo pronounced it “cool.”
You can tell that an article is basically approving when itr uses the word 'innovation'.