The consulting firm Booz Allen Hamilton said Tuesday that it had formally terminated Edward J. Snowden, the self-confessed source of leaked, classified National Security Agency documents about secret U.S. surveillance programs.

Booz Allen said Snowden was paid $122,000 a year for his work as a systems administrator on contract to the NSA, substantially less than the $200,00 a year he told reporters from The Washington Post and the Guardian newspaper that he made. Snowden was employed by Booz Allen for less than three months.

Federal investigators are examining how Snowden, 29, was able to gain access to what should be highly compartmentalized information, according to current and former administration and intelligence officials.

Snowden worked at an NSA Threat Operations Center in Hawaii, one of several such facilities that are tasked with detecting threats to government computer systems. He has previously worked for the CIA, U.S. officials said.

Snowden leaked documents to The Washington Post and Britain’s Guardian newspaper regarding distinctly different operations: the NSA’s collection of data from U.S. phone call records and its surveillance of online communications to and from foreign targets.

U.S. defense contractor Edward Snowden discusses his motivation behind the NSA leak and why he is revealing himself as the whistleblower behind the major story. (Nicki Demarco/Courtesy of Laura Poitras and Glenn Greenwald)

On Sunday, speaking from what he said was a hotel room in Hong Kong, he announced himself to the world as the source of the information, saying: “Allowing the U.S. government to intimidate its people with threats of retaliation for revealing wrongdoing is contrary to the public interest.”

A hotel receptionist in the city said Snowden had been staying there but checked out Monday. His current whereabouts are unknown.