The leaked intelligence material first appeared in a Discord chat room on which Mr Teixeira is said to have been an administrator. Its members would often discuss geopolitical affairs and wars.

The affidavit provided by FBI Special Agent Patrick Lueckenhoff to the court stated that the suspect began posting the leaked documents some time in December.

The initial leaks were in the form of paragraphs of text, according to the affidavit, but Mr Teixeira then moved on to posting photographs of documents in January.

It was not until intelligence material was posted outside the chat room group that Pentagon officials became aware of the leak, prompting a search for the culprit.

Mr Teixeira worked as an IT specialist in the intelligence wing of the Massachusetts National Guard, based at Otis Air National Guard Base in western Cape Cod.

The National Guard is a reservist wing of the US Air Force. They are not employed full-time in the military, but can be deployed when necessary.

Mr Teixeira's official title was cyber defence operations journeyman, according to the criminal complaint filed in the Boston court. He held the rank of Airman 1st Class - a relatively junior position.

The affidavit stated that Mr Teixeira held a "top secret" security clearance since 2021, and that he would have "signed a lifetime binding non-disclosure agreement" to take on his role.

Mr Luekenoff added the suspect "would have had to acknowledge that the unauthorized disclosure of protected information could result in criminal charges".

The affidavit also alleged that Mr Teixeira used his government computer to search classified intelligence reporting for the word "leak" on 6 April - the day when public reporting about the documents first emerged.

Prosecutors alleged that Mr Teixeira searched the term to learn whether US intelligence had information on the identity of the person behind the leaks.