Per the WaPo,
[....]Rear Adm. Mark H. Buzby, who said video surveillance recordings in several areas of the facility have been automatically overwritten and no longer exist.The legal term is obstruction of justice, and last I checked, it was still a crime.
"In January 2008, it was brought to my attention that such . . . [recording] systems may have been automatically overwriting video data contained on recording devices, at predetermined intervals," Buzby wrote. "That is, only a specified number of days' worth of recorded data could be retained on the recording devices at a time."
Defense lawyers said the admission suggests that the military has not complied with a 2005 court order to preserve such evidence, even if the deletion of the recordings was inadvertent. They claim that the tapes were of potential use at forthcoming court hearings and trials, a view supported by a Seton Hall University report slated to be released today.