By Josh Meyer
Los Angeles Times
SELLS, Ariz. — The reputed head of Mexico's Sinaloa drug cartel is threatening a more aggressive stance against competitors and law enforcement north of the border, 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 fugitive, would mark a turn from the cartel's previous position of largely avoiding violent confrontations in the U.S. -- either with law enforcement officers or rival traffickers.
Cartel leader threatens deadly force on U.S. police