It uses a Blair Witch conceit of "found footage", and like Blair Witch, it's a scripted, fictional film.
From The Hollywood Reporter:
In April 2002, when commercial director Christian Johnston and writing partner Christian Van Gregg completed the screenplay for a movie about an American journalist traveling to Afghanistan to search for Osama bin Laden, the pair didn't comprehend the magnitude of the project they had created.
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But all of those factors differentiate "Tapes" from so many other cutting-edge independent films debuting at next month's Sundance Film Festival in Park City. The final product offers proof that with the right equipment and a lot of luck, modern indie filmmakers can use cinema as both a storytelling medium and a powerful political tool.
In Hollywood terms, "Tapes" falls somewhere between 1999's "The Blair Witch Project" and 2001's "Black Hawk Down," a hybrid between traditional narrative and documentary. The film posits that U.S. journalist Don Larson, played by British actor George Calil (2001's HBO miniseries "Band of Brothers"), goes missing after traveling to the Middle East to make a documentary about bounty hunters searching for bin Laden and al-Qaida. Weeks later, Northern Alliance forces recover 18 of Larson's tapes and a microrecorder from an abandoned al-Qaida tunnel complex.
While Calil was working from a screenplay, Johnston frequently altered scripted scenarios during the shoot to reflect the reality of situations he and his team encountered. The effect is sometimes shocking: During certain sequences, bullets whizzing by onscreen are actual live ammunition.
http://www.hollywoodreporter.com/thr/international/feature_display.jsp?vnu_content_id=2058516