18 U.S. Code § 1512 - Tampering with a witness, victim, or an informant
(a)
(1) Whoever kills or attempts to kill another person, with intent to—
(A) prevent the attendance or testimony of any person in an official proceeding;
(B) prevent the production of a record, document, or other object, in an official proceeding; or
(C) prevent the communication by any person to a law enforcement officer or judge of the United States of information relating to the commission or possible commission of a Federal offense or a violation of conditions of probation, parole, or release pending judicial proceedings;
shall be punished as provided in paragraph (3).
(2) Whoever uses physical force or the threat of physical force against any person, or attempts to do so, with intent to—
(A) influence, delay, or prevent the testimony of any person in an official proceeding;
(B) cause or induce any person to—
(i) withhold testimony, or withhold a record, document, or other object, from an official proceeding;
(ii) alter, destroy, mutilate, or conceal an object with intent to impair the integrity or availability of the object for use in an official proceeding;
(iii) 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
(iv) be absent from an official proceeding to which that person has been summoned by legal process; or
(C) hinder, delay, or prevent the communication to a law enforcement officer or judge of the United States of information relating to the commission or possible commission of a Federal offense or a violation of conditions of probation, supervised release, parole, or release pending judicial proceedings;
shall be punished as provided in paragraph (3).
(3) The punishment for an offense under this subsection is—
(A) in the case of a killing, the punishment provided in sections 1111 and 1112;
(B) in the case of—
(i) an attempt to murder; or
(ii) the use or attempted use of physical force against any person;
imprisonment for not more than 30 years; and
(C) in the case of the threat of use of physical force against any person, imprisonment for not more than 20 years.
(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
(3) hinder, delay, or prevent the communication to a law enforcement officer or judge of the United States of information relating to the commission or possible commission of a Federal offense or a violation of conditions of probation [1] supervised release,, [1] parole, or release pending judicial proceedings;
shall be fined under this title or imprisoned not more than 20 years, or both.
(c) Whoever corruptly—
(1) alters, destroys, mutilates, or conceals a record, document, or other object, or attempts to do so, with the intent to impair the object’s integrity or availability for use in an official proceeding; or
(2) otherwise obstructs, influences, or impedes any official proceeding, or attempts to do so,
shall be fined under this title or imprisoned not more than 20 years, or both.
(d) Whoever intentionally harasses another person and thereby hinders, delays, prevents, or dissuades any person from—
(1) attending or testifying in an official proceeding;
(2) reporting to a law enforcement officer or judge of the United States the commission or possible commission of a Federal offense or a violation of conditions of probation [1] supervised release,, [1] parole, or release pending judicial proceedings;
(3) arresting or seeking the arrest of another person in connection with a Federal offense; or
(4) causing a criminal prosecution, or a parole or probation revocation proceeding, to be sought or instituted, or assisting in such prosecution or proceeding;
or attempts to do so, shall be fined under this title or imprisoned not more than 3 years, or both.
(e) In a prosecution for an offense under this section, it is an affirmative defense, as to which the defendant has the burden of proof by a preponderance of the evidence, that the conduct consisted solely of lawful conduct and that the defendant’s sole intention was to encourage, induce, or cause the other person to testify truthfully.
(f) For the purposes of this section—
(1) an official proceeding need not be pending or about to be instituted at the time of the offense; and
(2) the testimony, or the record, document, or other object need not be admissible in evidence or free of a claim of privilege.
(g) In a prosecution for an offense under this section, no state of mind need be proved with respect to the circumstance—
(1) that the official proceeding before a judge, court, magistrate judge, grand jury, or government agency is before a judge or court of the United States, a United States magistrate judge, a bankruptcy judge, a Federal grand jury, or a Federal Government agency; or
(2) that the judge is a judge of the United States or that the law enforcement officer is an officer or employee of the Federal Government or a person authorized to act for or on behalf of the Federal Government or serving the Federal Government as an adviser or consultant.
(h) There is extraterritorial Federal jurisdiction over an offense under this section.
(i) A prosecution under this section or section 1503 may be brought in the district in which the official proceeding (whether or not pending or about to be instituted) was intended to be affected or in the district in which the conduct constituting the alleged offense occurred.
(j) If the offense under this section occurs in connection with a trial of a criminal case, the maximum term of imprisonment which may be imposed for the offense shall be the higher of that otherwise provided by law or the maximum term that could have been imposed for any offense charged in such case.
(k) Whoever conspires to commit any offense under this section shall be subject to the same penalties as those prescribed for the offense the commission of which was the object of the conspiracy.
http://www.law.cornell.edu/uscode/text/18/1512
18 U.S. Code § 1510 - Obstruction of criminal investigations
(a) Whoever willfully endeavors by means of bribery to obstruct, delay, or prevent the communication of information relating to a violation of any criminal statute of the United States by any person to a criminal investigator shall be fined under this title, or imprisoned not more than five years, or both.
(b)
(1) Whoever, being an officer of a financial institution, with the intent to obstruct a judicial proceeding, directly or indirectly notifies any other person about the existence or contents of a subpoena for records of that financial institution, or information that has been furnished in response to that subpoena, shall be fined under this title or imprisoned not more than 5 years, or both.
(2) Whoever, being an officer of a financial institution, directly or indirectly notifies—
(A) a customer of that financial institution whose records are sought by a subpoena for records; or
(B) any other person named in that subpoena;
about the existence or contents of that subpoena or information that has been furnished in response to that subpoena, shall be fined under this title or imprisoned not more than one year, or both.
(3) As used in this subsection—
(A) the term “an officer of a financial institution” means an officer, director, partner, employee, agent, or attorney of or for a financial institution; and
(B) the term “subpoena for records” means a Federal grand jury subpoena or a Department of Justice subpoena (issued under section 3486 of title 18), for customer records that has been served relating to a violation of, or a conspiracy to violate—
(i) section 215, 656, 657, 1005, 1006, 1007, 1014, 1344, 1956, 1957, orchapter 53 of title 31; or
(ii) section 1341 or 1343 affecting a financial institution.
(c) As used in this section, the term “criminal investigator” means any individual duly authorized by a department, agency, or armed force of the United States to conduct or engage in investigations of or prosecutions for violations of the criminal laws of the United States.
(d)
(1) Whoever—
(A) acting as, or being, an officer, director, agent or employee of a person engaged in the business of insurance whose activities affect interstate commerce, or
(B) is engaged in the business of insurance whose activities affect interstate commerce or is involved (other than as an insured or beneficiary under a policy of insurance) in a transaction relating to the conduct of affairs of such a business,
with intent to obstruct a judicial proceeding, directly or indirectly notifies any other person about the existence or contents of a subpoena for records of that person engaged in such business or information that has been furnished to a Federal grand jury in response to that subpoena, shall be fined as provided by this title or imprisoned not more than 5 years, or both.
(2) As used in paragraph (1), the term “subpoena for records” means a Federal grand jury subpoena for records that has been served relating to a violation of, or a conspiracy to violate, section 1033 of this title.
(e) Whoever, having been notified of the applicable disclosure prohibitions or confidentiality requirements of section 2709 (c)(1) of this title, section 626(d)(1) or 627(c)(1) of the Fair Credit Reporting Act (15 U.S.C. 1681u (d)(1) or 1681v (c)(1)),section 1114(a)(3)(A) or 1114(a)(5)(D)(i) of the Right to Financial Privacy Act [1] (12 U.S.C. 3414 (a)(3)(A) or 3414 (a)(5)(D)(i)), orsection 802(b)(1) of the National Security Act of 1947 (50 U.S.C. 436 (b)(1)), [2] knowingly and with the intent to obstruct an investigation or judicial proceeding violates such prohibitions or requirements applicable by law to such person shall be imprisoned for not more than five years, fined under this title, or both.
http://www.law.cornell.edu/uscode/text/18/1510
18 U.S. Code § 1505 - Obstruction of proceedings before departments, agencies, and committees
Whoever, with intent to avoid, evade, prevent, or obstruct compliance, in whole or in part, with any civil investigative demand duly and properly made under the Antitrust Civil Process Act, willfully withholds, misrepresents, removes from any place, conceals, covers up, destroys, mutilates, alters, or by other means falsifies any documentary material, answers to written interrogatories, or oral testimony, which is the subject of such demand; or attempts to do so or solicits another to do so; or
Whoever corruptly, or by threats or force, or by any threatening letter or communication influences, obstructs, or impedes or endeavors to influence, obstruct, or impede the due and proper administration of the law under which any pending proceeding is being had before any department or agency of the United States, or the due and proper exercise of the power of inquiry under which any inquiry or investigation is being had by either House, or any committee of either House or any joint committee of the Congress—
Shall be fined under this title, imprisoned not more than 5 years or, if the offense involves international or domestic terrorism (as defined in section 2331), imprisoned not more than 8 years, or both.
http://www.law.cornell.edu/uscode/text/18/1505