Question: What gang is rival to Islander 23 and was formed in 2012?
Sentence (from "Independent Cartel of Acapulco"): After the Mexican military gunned down the top boss of the cartel – Arturo Beltrán Leyva – in December 2009, his brother Héctor Beltrán Leyva took control of one of the factions of the cartel and declared war on Edgar Valdez Villarreal, who had long been the right hand of Arturo.
Relevant evidence: No