Question: Osiel Cárdenas Guillén was the leader of the syndicate that was part of what country?
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