The U.S. Supreme Court in Quinn v. United States also recognized certain limitations on Congressional power to investigate and summon individuals, namely, that it “cannot be used to inquire into private affairs unrelated to a valid legislative purpose. Nor does it extend to an area in which Congress is forbidden to legislate. Similarly, the power to investigate must not be confused with any of the powers of law enforcement; those powers are assigned under our Constitution to the Executive and the Judiciary.
Also, maximum penalty is $1000 fine+12 months in prison.
Also, maximum penalty is $1000 fine+12 months in prison.
https://www.law.cornell.edu/wex/contempt_of_congress