noun
1. : a legal proceeding carried on for the primary purpose of interrogating an adversary or examining his property or books, papers, and records in order to discover information essential to and to be used as a basis for a later proceeding or defense
2. : an investigation that has no clearly defined objective or that does not stick to its stated or authorized objective and that engages in expedients of doubtful propriety or legality (as the irrelevant questioning of witnesses) in the hope of turning up incriminating or newsworthy evidence
promised at the outset of the investigation that it would not … degenerate into a witch-hunt or a fishing expedition — Tom Fitzsimmons