Question: In which region is this crminal group based whose leader served as the right hand of Arturo Beltrán Leyva who was gunned down by the Mexican military?
Sentence (from "Héctor Beltrán Leyva"): Héctor Beltrán Leyva (born 15 February 1965) is a Mexican suspected drug lord and former leader of the Beltrán Leyva Cartel, a drug trafficking organization.
Relevant evidence: No