Luis Fredy Lala Pomavilla, an Ecuadorean citizen who survived a massacre that left 72 Central and South American migrants dead at a ranch 100 miles south of the U.S.-Mexican border, rests at a hospital in Matamoros on Aug. 24. He said the killers said they belonged to the Zetas drug cartel. (Associated Press)

Luis Fredy Lala Pomavilla, an Ecuadorean citizen who survived a massacre that left 72 Central and South American migrants dead at a ranch 100 miles south of the U.S.-Mexican border, rests at a hospital in Matamoros on Aug. 24. He said the killers said they belonged to the Zetas drug cartel. (Associated Press)