A Chinese national hired at the Arizona Counterterrorism Information Center may have stolen data from the agency before abruptly flying back to China without notifying his superiors — a possible security breach the agency has been covering up since 2007.

Lizhong Fan was hired as a facial recognition expert for the agency in 2007 until he left suddenly in June of the same year after erasing his work computers completely, destroying any record of his activities. Fan flew back to Beijing with two laptops and multiple hard drives in his luggage, according to a joint report by Pro Publica and The Center for Investigative Reporting, and he did not notify his bosses before leaving.

After disappearing Fan sent emails expressing a desire to return to the U.S. sometime in the future, but no one has reportedly received any communications from Fan in more than three years.

While working at the center Fan had access to almost all stored data, including five million drivers’ licenses, information about intelligence analysts and investigators, and other sensitive law enforcement databases.

As a current Chinese citizen Fan should have been disqualified during vetting for the position, but may have gained entry through other subversive means. Fan was contracted out to the center as an employee for Hummingbird Defense Systems, an Arizona-based firm contracted to build the center’s facial recognition system. Fan reportedly built a similar system for the Chinese government.

Fan got a job recommendation from Xunmei Li — the girlfriend of Hummingbird CEO Steve Greschner. The FBI now suspects Li may have also been a spy for the Chinese.

According to the report, deputies of Maricopa Country Sheriff Joe Arpaio seemingly worked to keep the possible breach a secret by telling officers to stay silent. Neither the sheriff himself nor Homeland Security Chief Janet Napolitano have said anything about the situation in the seven years since Fan went back to China.

The disclosure comes after the recently reported hack of the U.S. Investigations Services, which revealed the social security numbers and birth dates of more than 25,000 Homeland Security employees.

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