In court papers, they said the investigation of Kiriakou began in 2009 when authorities became alarmed after discovering that detainees at Guantanamo Bay possessed photographs of CIA and FBI personnel who had interrogated them. The investigation eventually led back to Kiriakou, according to a government affidavit.

The papers indicated that prosecutors believed Kiriakou had leaked the name of a CIA covert operative to a journalist, who disclosed it to an investigator working for the lawyer of a Guantanamo detainee.