The Justice Department investigation started by Attorney General Eric Holder is trying to determine who gave information on the Stuxnet virus to The New York Times, The Washington Post and other media outlets. Stuxnet and a sister virus called Flame were created by U.S. and Israeli cyberintelligence workers and used to infiltrate Iran's nuclear facility. Once installed, Stuxnet caused the enrichment centrifuges to spin out of control and break.
Justice Department officials said only a select handful of U.S. and Israeli officials had knowledge of the Stuxnet program and officials "at pretty high levels" are being questioned about the leaks, one official familiar with the investigation told the Washington Post.
The Obama administration has prosecuted six individuals for leaking classified information to reporters -- more than all other presidential administrations combined.
The Post said the advent of email -- and software that easily allows prosecutors to search large quantities of it in mere seconds -- has helped create a trail for investigators to follow.