Mexicans soldiers guard Juan Francisco Sillas Rocha, a top operative of the Arellano Felix drug cartel, in Mexico City, on November 7, 2011. Mexican army troops have arrested a top operative of the once-powerful Arellano Felix drug cartel in the northwestern state of Baja California. Juan Francisco Sillas Rocha, alias “El Sillas”, and three associates were arrested over the weekend in the...