Frank Ponce de Leon, a native of Mexico who lives in La Puente, Calif., spent almost three months in immigration custody — all the while insisting he was a U.S. citizen. Photo: Anne Cusack / Los Angeles Times Rennison Vern Castillo thought his legal troubles were nearly over at the end of a jail stay

EL PASO—The Juarez police lieutenant was recovering from three gunshot wounds, the result of an assault by hit men for a drug cartel. His name was on a death list brazenly posted at a monument for fallen peace officers. Lt. Salvador Hernandez Arvizu didn't like his odds of surviving in Mexico. So he fled his