A group suspected of stealing secret files on potential terrorists in San Diego and elsewhere apparently operated with impunity from one of Camp Pendleton’s most heavily guarded buildings, newly obtained court records and investigative reports show. Its members – military reservists and law enforcement officers – allegedly swiped the classified documents from the Strategic Technical Operations Center.Base officials have acknowledged the center’s existence without discussing anything about it, citing national security concerns. But FBI and Navy agents said in reports that Col. Larry Richards, a Marine reservist, and his accomplices had no trouble evading the building’s security measures.