fishing expeditionfishing expedition
a wide-ranging, often unwarranted investigation, interrogation, etc. carried out in the hope of uncovering any unspecified incriminating or compromising information
An open-ended inquiry or investigation, often undertaken on the pretext of a minor or unrelated matter, whose real purpose is to uncover embarrassing or damaging information, as about a political opponent.
(plural fishing expeditions)
- (idiomatic, law, US, informal, pejorative) A non-specific search for information, especially incriminating information.