The Bureau of Land Management shredded documents before leaving their camp during the armed standoff with Cliven Bundy in 2014 near his Bunkerville ranch.
Officials say this was done to protect sensitive information.
Officers feared they would be overrun by Bundy supporters and didn't want that information to fall into "the hands of persons engaged in criminal activity."
Bundy and 16 others have pleaded not guilty to various charges stemming from the standoff that stopped government agents from rounding up cattle on public land.