https://www.law.cornell.edu/uscode/text/18/1512
(b)Whoever knowingly uses intimidation, threatens, or corruptly persuades another person, or attempts to do so, or engages in misleading conduct toward another person, with intent to—
(1)influence, delay, or prevent the testimony of any person in an official proceeding;
(2)cause or induce any person to—
(A)withhold testimony, or withhold a record, document, or other object, from an official proceeding;
(B)alter, destroy, mutilate, or conceal an object with intent to impair the object’s integrity or availability for use in an official proceeding;
(C)evade legal process summoning that person to appear as a witness, or to produce a record, document, or other object, in an official proceeding; or
(D)be absent from an official proceeding to which such person has been summoned by legal process; or