Washington — Investigators are now uncertain how long computer disks containing nuclear secrets were missing from a Los Alamos laboratory vault. The last written record was made right after New Year's Day as part of the Y2K rollover tests, government sources said Tuesday.
The lab's director and senior Energy Department security officials have said the two hard drives, which were recovered last week and are being electronically scrutinized for security lapses, were last reported seen by a Los Alamos scientist in the vault April 7.
Sources familiar with the investigation said Tuesday that this account, although not entirely dismissed, has come under suspicion because of some "conflicting statements" made during interviews and polygraph tests.
Energy Secretary Bill Richardson sidestepped any discussion of the latest Los Alamos controversy but planned to appear today at a Senate Armed Services Committee hearing. Republican lawmakers have criticized him vigorously for the security breach, some calling for his resignation.
The computer drives, used by an emergency nuclear response team at Los Alamos, contain secret technical data on U.S. and some foreign nuclear devices to be used in finding and dismantling a device in an accident or terrorist attack.
They were discovered missing on May 7 from the vault in the highly secured "X Division" complex of the Los Alamos weapons lab in New Mexico, a day before the lab was evacuated because of a threat from raging wildfire. The disappearance was not reported until May 31, when the report unleashed a desperate search and a criminal investigation.
Last Friday, the storage disks were found under suspicious circumstances behind a copying machine not far from the vault in an area previously searched several times, officials said.