Retired Marine Corps Gen. James “Hoss” Cartwright was vice chairman of the Joint Chiefs of Staff and somewhat of a White House fixture as a close military adviser to President Obama.

For over a year, he reportedly has been the target of a Justice Department criminal investigation. He is suspected of leaking to The New York Times highly classified details of a U.S. cyberwarfare program against Iran and its quest for nuclear weapons. Gen. Cartwright played a critical role in the covert action, whose weapon was a cyberworm called Stuxnet and whose code name was “Olympic Games.”

The Washington Post reported Wednesday that the probe has come to a halt because the White House fears prosecution would force the administration to disclose secret sources and methods.