By Barbara Starr

The former vice chairman of the U.S. Joint Chiefs of Staff is under investigation by the Justice Department regarding material in a book by David Sanger, a correspondent for The New York Times, a source directly familiar with the situation said Thursday.

The source could not confirm that the investigation involving Retired Marine Gen. James Cartwright is specifically about the Stuxnet computer virus, which Sanger writes about in his 2013 book "Confront and Conceal: Obama's Secret Wars and Surprising Use of American Power."

NBC News reported Thursday, citing legal sources, that Cartwright has been told he's under investigation for allegedly leaking classified information about Stuxnet, a complex virus that infected computers in Iranian nuclear facilities in 2010.

That leak was one of a series of national security-related leaks last year and had details of how the United States and Israel were behind the Stuxnet attack.