Killing of a Witness - whoever kills or attempts to kill another person, with intent to prevent the attendance or testimony of any person in an official proceeding; prevent the production of a record, document, or other object, in an official proceeding; or 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.
Source: http://www.law.cornell.edu/uscode/text/18/1512
Source: http://www.law.cornell.edu/uscode/text/18/1512
