Though sounds like a chapter in Tom Clancy's technothriller, this doctored report scandal is for real. United Nations - in its investigation report on the assassination of Rafik Hariri (ex-Lebanese Prime Minister) - simply dropped some names and changed them to unnamed reference e.g. "officials". However, the original version was possible to be easily constructed because changes were made using the track changes feature of Microsoft Word and apparently somebody forgot to click Accept All Changes, thus leaving the changes intact.
You can see yourself the HTML-version of the document. The parts striked in red were deleted later for the final draft, but these still exist and quite readable.