The Pentagon. Photo: David B. Gleason/Flickr.

i24 News – The leading suspect in the investigation of the leak of highly classified US intelligence documents – deemed as the most serious security breach in a decade – was identified by media on Thursday as 21-year-old Jack Teixeira, an Air National guardsman who worked on a military base.

According to The New York Times, Teixeira went by the nickname “OG” and ran an online group called “Thug Shaker Central” for like-minded teens and men who discussed their shared love of guns, racist online memes, and video games. Reuters said the suspect was expected to be arrested later in the day.

Earlier on Thursday, US President Joe Biden said investigators were closing in on the source of the leak, a week after the Justice Department launched a probe into the possible leak of Pentagon documents that were posted on social media and appeared to detail American spy efforts on Russia as well as developments in Israel.

“There’s a full-blown investigation going on, as you know, with the intelligence community and the Justice Department, and they’re getting close but I don’t have an answer,” Biden told reporters in Ireland.

“I’m not concerned about the leak, I’m concerned that it happened. But there is nothing contemporaneous that I’m aware of,” he added.

The leaked documents – although still unauthenticated with some attributing them to being part of a misinformation campaign – were labeled “secret” and resembled routine updates that the US military’s Joint Chief of Staff would produce daily but not distribute to the public. They were dated ranging from February 23 to March 1, and detailed the progress of weapons and equipment going into Ukraine as well as US spying efforts on Russian security services, NYT first reported.

More documents that appeared later suggested that Israel “likely will consider providing lethal aid” to Ukraine “under increased US pressure or a perceived degradation” in its relationship with Russia. They also charged that the Mossad, Israel’s spy agency, encouraged Israelis to participate in mass protests against the government’s judicial reform plan.

The Post reported later on Thursday that more leaked documents revealed that China approved the “provision of lethal aid” to Russia in its war in Ukraine earlier this year and planned to disguise military equipment as civilian items.