The new charges against former President Donald Trump over his alleged mishandling of classified documents were outlined in what's known as a superseding indictment.

It's a document that amends and replaces the original indictment, listing the formal charges against a defendant.

A grand jury typically approves a superseding indictment after additional information or evidence has been obtained, and the new document usually adds charges or defendants to the case. However, in rare instances, minor deletions of details included in the initial indictment have been permitted.

The superseding indictment shows that special counsel Jack Smith has expanded his case. Trump, who was first indicted in this case last month, now faces three additional criminal charges: one additional count of willful retention of national defense information and two additional obstruction counts.

Among the new information listed in the superseding indictment, Trump allegedly willfully retained a top-secret document that was a "presentation concerning military activity in a foreign country" -- which CNN previously reported was Iran -- and discussed the document with biographers during a taped meeting in July 2021.

Prosecutors also added a third defendant, Carlos De Oliveira, to the case and accused the Mar-a-Lago employee of working alongside Trump and his aide Walt Nauta -- who was listed in the initial indictment -- of obstructing the investigation by attempting to delete Mar-a-Lago security footage sought by the grand jury.

Trump and Nauta have pleaded not guilty. De Oliveria is expected to be arraigned next week in Miami.