NEW : Authorities notified the sheriff 's office of a formal investigation a year later , a statement said . Sheriff John Arpaio suggests Justice Department investigation is politically motivated . Justice Department investigation details slurs and language used against Hispanics . Feds probe how sheriff 's office handled 432 cases of sexual assault and child molestation . Assistant attorney general say sheriff 's office failed to cooperate in the probe .
NEW : Sheriff John Arpaio suggests Justice Department investigation is politically motivated . Justice Department investigation details slurs and language used against Hispanics . Feds probe how sheriff 's office handled 432 cases of sexual assault and child molestation . Assistant attorney general say sheriff 's office failed to cooperate in the probe .