18 U.S.C. Sec. 1512(B)(2)(B) prohibits witness tampering by altering or destroying evidence. This includes any act committed with the intent to prevent the communication of information relating to the commission of a federal offense to a federal law enforcement officer, judge, or other official, or to prevent the production of such information in an official proceeding. Examples of such conduct include altering, destroying, or concealing evidence, intimidating a witness, or attempting to influence a witness's testimony. There are two types of witness tampering under 18 U.S.C. Sec. 1512(B)(2)(B): alteration or destruction of evidence, and intimidation or attempt to influence a witness's testimony.