A cartel leader and hitman fond of videotaping torture sessions and decapitating his enemies has gone missing from a federal prison in Florida, where he was serving a 49-year sentence. As of November, Edgar Valdez-Villareal, a Mexican-American cartel leader, had been mysteriously removed from the federal Bureau of Prisons web site. He is now listed as “not in BOP custody” even though his release date is not until July 27, 2056. Valdez-Villareal, 49, is known by his underworld moniker “La Barbie,” and headed up the the Los Negros, an enforcement group of the Beltran Leyva cartel — one of Mexico’s...