The intentional deletion or alteration of a document used as legal evidence. Since the advent of personal computers, it has become a snap to alter a document without revealing the alteration. If the document remains in the same computer where the alteration took place, or if that computer is available for analysis, an alteration may be uncovered with computer forensics. However, if the altered document is transferred to another machine by a savvy user, who knows how to delete all associated meta-data that might be under the covers, it is impossible to detect the document's previous history. See computer forensics.