AdvertisementDrug Cartels Prey On Migrants Crossing MexicoJuly 07, 2011Jason BeaubienfacebookEmailPolice officers stand next to a hole they say was used as a mass grave near San Fernando in the Mexican state of Tamaulipas in late April. Almost 200 bodies were found that month in Tamaulipas. Prosecutors believe the killings were carried out by members of the Zetas drug cartel. (AP)