The contractor, John C. Kingsley, said in court documents filed in the case that he discovered the Russians' role after he was appointed to run one of the firms in 2010. He said the software they wrote had made it possible for the Pentagon's communications systems to be infected with viruses.

Greed drove the contractor to employ the Russian programmers, he said in his March 2011 complaint, which was sealed until late last week. He said they worked for one-third the rate that American programmers with the requisite security clearances could command. His accusations were denied by the firms that did the programming work.

"On at least one occasion, numerous viruses were loaded onto the DISA [Defense Information Systems Agency] network as a result of code written by the Russian programmers and installed on servers in the DISA secure system," Kingsley said in his complaint, filed under the federal False Claims Act in U.S. District Court in Washington, D.C., on March 18, 2011.