A man falsely claiming to be an FBI agent showed up to a federal jail in New York City on Wednesday night and told officers he had a court order to release Luigi Mangione, authorities said. Stream San Diego News for free, 24/7, wherever you are with NBC 7. Anderson was expected to make an initial appearance Thursday in Brooklyn federal court. The attempt to free Mangione happened during a critical stretch in his legal cases. Accused killer Luigi Mangione, facing charges in the murder of UnitedHealthcare CEO Brian Thompson was back in court Tuesday.