Question: Mario Cárdenas Guillén is the brother of the Mexican drug lord who was the former leader of what group?
Sentence (from "Osiel Cárdenas Guillén"): Osiel Cárdenas eventually took control by killing his friend and contender Salvador Gómez, earning Cárdenas the nickname ""El Mata Amigos"" (The Friend-Killer).
Relevant evidence: No