The two people who discussed the development were not authorized to discuss an ongoing investigation publicly and spoke on condition of anonymity to The Associated Press.
The New York Times earlier reported the FBI’s interest in the person.
The Justice Department and FBI have narrowed the pool of potential suspects believed responsible for the disclosure of highly classified military documents on the Ukraine war, a person familiar with the investigation said Thursday.
The Biden administration has been working to assess the diplomatic and national security consequences of the leaked documents since they were first reported last week. A top Pentagon spokesman told reporters earlier this week that the disclosures present a “very serious risk to national security,” and the Justice Department opened an investigation to identify the person responsible.
“We’re getting close,” President Joe Biden told reporters in Ireland on Thursday. He said that though he was concerned that sensitive government documents had been disclosed, “there’s nothing contemporaneous that I’m aware of that is of great consequence.”
Since the investigation began, officials have winnowed down the number of suspects who might be responsible, according to a person with knowledge of the probe who was not authorized to discuss an ongoing investigation. It was not clear how many suspects remained or when or if an arrest might be made.
The Justice Department declined to comment Thursday.
It’s possible the leak may have started on a site called Discord, a social media platform popular with people playing online games. The Discord site hosts real-time voice, video and text chats for groups and describes itself as a place “where you can belong to a school club, a gaming group, or a worldwide art community.”
In one of those forums, originally created to talk about a range of topics, members would debate the war in Ukraine. According to one member of the chat, an unidentified poster shared documents that the poster claimed were classified, first typing them out with the poster’s own thoughts, then, as of a few months ago, uploading images of folded papers.
Discord has said it was cooperating with law enforcement.
There are only a few ways the classified information that was leaked could have been accessed, which may provide critical clues as to who is responsible. Typically in classified briefings, as with the slides that were placed on Discord, the information is shared electronically.
That is done either through secure computer terminals where users gain access based on their credentials or through tablets that are distributed for briefings and collected afterward. If the slides need to be printed out instead, they can only be sent to secured printers that are able to handle classified documents — and that keep a digital record of everyone who has requested a printout.
It’s those digital clues like the record of printouts that may help investigators hone in on who took the documents. In most of the photographs of documents posted online the pictures are of paper copies that look like they had been folded into quarters — almost as if they’d been stuffed into someone’s pocket.
In the days since the leaks came to light, the Pentagon has deferred questions on the investigation to the Justice Department, stating that it’s a criminal matter. Even if the person who leaked the files is an active duty member of the U.S. military, the Justice Department would likely still have the lead in the prosecution until it was ready to turn the matter over to the Defense Department, a defense official told the AP on the condition of anonymity to discuss sensitive matters.
This has been the case in previous criminal cases, such as when two Marines based at Camp Pendleton in California were arrested on drug trafficking charges in 2020, the official said. If the person responsible turns out to be a civilian, the Justice Department will be responsible, the official said.
CNN reported earlier Thursday that the FBI believed it was getting close to identifying a suspect.
Associated Press writers Colleen Long and Darlene Superville in Dublin contributed to this report.