New charges against Trump are part of what is called superseding indictment - document that updates original charges       

Former President.Donald Trump. AFP/File

Former President Donald Trump is facing more serious charges related to how he handled secret documents. 

The new charges are part of what is called a "superseding indictment," which is a document that changes and updates the original charges against a defendant.

A group of people called a grand jury decides if the superseding indictment is necessary after getting more information or evidence. Usually, this new document adds more charges or names more people involved in the case. Sometimes, they might remove some small details from the original indictment.

In this case, special counsel Jack Smith has expanded the charges against Trump. Last month, Trump was charged with a crime in connection to mishandling classified documents. Now, he faces three more criminal charges. One of the new charges is about keeping secret national defense information deliberately. The other two charges are about obstructing, or trying to interfere with, the investigation.

According to the new information in the superseding indictment, Trump allegedly kept a top-secret document about military activities in another country, possibly Iran. He discussed this document with biographers during a recorded meeting in July 2021.

In addition to Trump, the prosecutors have also included another person, Carlos De Oliveira, as a defendant in the case. They say that De Oliveira, who works at Mar-a-Lago, was involved in obstructing the investigation. They claim he worked with Trump and Trump's aide, Walt Nauta, who was mentioned in the original indictment. They say they tried to delete security camera footage from Mar-a-Lago that the grand jury wanted to see.

Both Trump and Nauta have said they are not guilty of the charges against them. De Oliveira will be formally charged in Miami next week.