LAREDO — In the face of the impunity under which Mexican drug cartels operate along the border, police here secured an arrest warrant for Miguel Treviño Morales, identified as a high-ranking regional Gulf Cartel leader, in connection with a 2006 double homicide. A police official confirmed Treviño was a wanted man after his name appeared in a probable cause affidavit for another defendant in the same case. Juan "Cordless" Ramos, 24, was arrested Tuesday in Laredo in connection with the April 2, 2006, shooting deaths of Jesus Maria Resendez, 36, and his nephew Mariano Resendez, 15, just inside the city...