SAN ANTONIO (AP) — A Mexican immigration official says that in the chaotic minutes after dozens of migrants were found dead inside a tractor-trailer sweltering in the Texas heat, the driver tried to slip away by pretending to be one of the survivors. The driver and two other men from Mexico remained in custody Wednesday as the investigation continued into the tragedy that killed 53 people in the nation’s deadliest smuggling episode on the U.S.-Mexico border. The head of Mexico’s National Immigration Institute says at least 27 of the victims were from Mexico, 14 were from Honduras, seven were from Guatemala and two were from El Salvador.