WikiScanner, developed by CalTech graduate student Virgil Griffith, has traced editorial changes made to the online encyclopedia to FBI and CIA computers, including the removal of satellite imagery of the Guantanamo prison camp on the island of Cuba, where the United States has detained suspected terrorists since 2002, and redactions of articles on the invasion of Iraq in 2003.
The program revealed that the CIA edited entries about its former director, William Colby, altering details of his career, and that a graphic on casualties in Iraq was manipulated to downplay the figures.
A number of commercial companies were also found to have edited entries related to them, in clear violation of Wikipedia's editorial guidelines that disqualify people or organizations from editing articles that concern them directly.
However, a spokeswoman for Wikipedia's parent company, Wikimedia, said the online encyclopedia was in any event self-correcting, and that any misleading entries are usually quickly rectified.
The FBI did not have any comment, and the CIA insisted that all of its computers are used responsibly.