Donald Trump is accused of pressuring an employee to delete security footage at his Florida home, in new criminal charges related to his alleged mishandling of classified files.
The new indictment adds one count of wilful retention of defence information and two of obstruction, making 40 charges in total in this case.
Mr Trump denies any wrongdoing and has called the prosecutor “deranged”.
He is fighting multiple legal cases as he runs for president again.
In a Friday morning interview, he reiterated that he would not end his 2024 campaign even if he is criminally convicted.
Mr Trump has pleaded not guilty to earlier charges in the case, alongside his personal aide Walt Nauta, who also received two additional charges of obstruction on Thursday.
The property manager at the former US president’s Mar-a-Lago estate, Carlos de Oliveira, has also now been indicted.
The revised charge-sheet outlines alleged efforts between Mr Nauta and Mr de Oliveira to obstruct the justice department’s investigation.
According to the court document, they conspired in an effort to delete surveillance video after the Department of Justice issued a subpoena demanding footage of the area where it said confidential documents were held.
Prosecutors claim Mr de Oliveira twice told Mar-a-Lago’s director of information technology that “the boss” wanted the server deleted, in a conversation he said must remain between them.
The IT worker responded that he did not believe he had the authority to do so, according to the indictment.
The employee, who is not named or charged in the indictment, has been identified as Yuscil Taveras.
The charge-sheet also describes a scene in which Mr de Oliveira “walked through the bushes” into a property adjacent to the Mar-a-Lago resort to meet Mr Nauta.
Later, the court filing adds, Mr Trump phoned Mr de Oliveira and promised him legal counsel at Mr Nauta’s request.
A lawyer for Mr de Oliveira has declined to comment on the allegations.
The updated indictment also says that Mr Trump knowingly discussed a top-secret document with biographers visiting Mar-a-Lago to interview him.
The paper Mr Trump allegedly revealed to the biographers contained possible plans to attack “Country A”, which refers to Iran.
“Look what I found… Isn’t it amazing? I have a big pile of papers, this thing just came up. Look,” Mr Trump allegedly said to one of his guests.
The documents case is led by special prosecutor Jack Smith, who is also overseeing a separate investigation into alleged efforts to overturn the results of the 2020 election.
Earlier on Thursday, Mr Trump’s attorneys John Lauro and Todd Blanche met officials at Mr Smith’s office in Washington DC.
The former president said on Thursday his lawyers had received no indication of timing of when charges may be filed in the case.
In an emailed statement, his presidential campaign dismissed the fresh charges as a “way to salvage their illegal witch hunt”.
Congressional Republicans also defended Mr Trump against what many in the party have called a “weaponised Department of Justice”.
Missouri Senator Josh Hawley suggested the charges had been timed to distract from the collapse of a plea deal for President Joe Biden’s son, Hunter, over tax and gun offences.
Mr Biden is also facing a special counsel investigation into his handling of classified documents, some of which were discovered in a garage at his home in Wilmington, Delaware.
But on Friday, a former Trump lawyer said his ex-client is in for “a tight case, the evidence is so overwhelming”.
“I think this original indictment was engineered to last a thousand years and now this superseding indictment will last an antiquity,” Ty Cobb, who represented Mr Trump early in his presidency, told CNN.
The latest charge against Mr Trump adds to a growing list of legal problems for the property and reality TV mogul.
He currently awaits trial on 34 felony counts in a hush-money case in New York, and also faces civil charges in a defamation case against author E Jean Carroll.
Georgia prosecutors are still weighing whether or not to press state charges over an alleged effort to overturn the election results there.
Former Trump aide Stephen Moore told the BBC the charges against the former president would only serve to solidify his nomination in the Republican presidential race.
“The more they indict him, the more his popularity goes up with Republicans”, he told BBC Radio 4’s Today programme.
BBC