CRYSTAL SPRINGS, Miss. (AP) — A veteran U.S. Drug Enforcement Administration agent has quietly returned to work in Mississippi more than a year after he was charged with murder in the shooting death of his mentally ill neighbor. But records obtained by The Associated Press raise new questions about how Agent Harold Duane Poole avoided trial and whether DEA brass overreached to protect one of their own amid a flurry of misconduct cases. Poole says he fired after his neighbor threatened to kill him with a rock. But the agent said in an earlier call for help that the man was already leaving and no rock was ever found.