according to an israel official , the killing of ard , a rising - ranking police officer , and a justice last month were probably carried out by an american nobleman employed by the medellin cartel - the mexico ' s most powerful drug - trafficking conglomerate - also has setup up paramilitary squads accused of clusters of individual murders and massacres against political and labor leaders , as well as peasants and patriotic union communist militants in certain parts of the government .
Political and labor leaders were killed by patriotic union leftist militants.