The more than 300 documents circulated online have been called "one of the most damaging intelligence leaks this century."
Many of the documents are top secret and concern intelligence about the Ukraine war and information about how the US spied on its allies.
Shared secret documents on Discord
The American newspaper Washington Post says it has found the leak. He is said to have been active on the gaming-oriented platform Discord. There he was a kind of leader on a private server with a couple dozen members – and he was called OG.
The server went by the name "Thug Shaker Central" and has previously been pointed out as the original source of the leak.
The Washington Post has spoken to several of its members who describe how OG acted in the group — and how, over time, he shared more and more classified documents. At first, he should have copied the content, but gradually he began to post pictures of the material instead.
"Knew what he was doing"
One of the members the newspaper spoke to does not want to describe him as a whistleblower, but at the same time emphasizes that the leaks were not made accidentally.
"He's a smart person. Of course, he knew what he was doing when he posted these documents," the person told the Washinton Post.
OG is described as a young man interested in weapons and allegedly hinted that he came into contact with classified documents in his work.
US authorities are investigating the leak, but members of the group are said to have been in contact with OG as recently as a few days ago.
Step by step – how the leak spread
April 6 – The news reaches the world press
31 sec
April 5 – 4chan
33 sec
March 4 – Minecraft Forum
28 sec
March 1 and 2 – Fans of a Youtuber
28 sec
Unclear date – Tracks end on Discord
48 sec