They entered the airport a week ago, identified themselves as employees of the airport's computer services provider and cleared to enter the customs division's mainframe room, protected by top-level airport security requirements.
According to the Sydney Morning Herald on Friday, the Australian Federal Police and the ASIO (Australian Security Intelligence Organisation), the two chief guardians against “terrorism”, fired off angry memos to customs officials.
They demanded to know the extent to which their top-secret operations had been compromised.
The Australian Customs Services told officers in an email no sensitive operational information was lost, the Herald said.
However customs officers said the two mainframe servers at Sydney International Airport held thousands of confidential files, including top-secret communications between customs investigators and the federal police and the ASIO.