SELLS, Ariz. – The reputed head of Mexico’s Sinaloa drug cartel is threatening a more aggressive stance against U.S. law enforcement, instructing associates to use deadly force, if needed, to protect increasingly contested trafficking operations, authorities said. Such a move by Joaquin “El Chapo” Guzman, Mexico’s most-wanted man, would mark a turn from the cartel’s previous position of largely avoiding violent confrontations north of the border – either with American law enforcement officers or fellow traffickers. Local police and federal agents in Arizona said they recently have received at least two law enforcement alerts focused on Guzman’s reported orders that...
