Former US President Donald Trump is accused of pressuring an employee to delete security footage at his Florida estate to obstruct the investigation into the classified documents case.
The new charges relate to Mr Trump’s alleged handling of government documents at Mar-a-Lago.
Mr Trump has now been charged with one count of wilful retention of defence information and two of obstruction.
Prosecutors say the footage shows illegally-held files being moved.
Mr Trump has pleaded not guilty alongside his close aide Walt Nauta, who also received two additional charges of obstruction on Thursday.
According to the new court documents, Mr Nauta and Mr de Oliveira conspired to delete footage from security cameras after the Department of Justice issued a subpoena asking for surveillance footage of the basement where it said confidential documents were held.
In the court documents, Mr de Oliveira is claimed to have texted another employee who was the director of information technology that “the boss” wanted the server deleted.
The documents allege that Mr de Oliveira later met with the employee in a small IT room, told him their conversation should remain private, then pressured the man into obliging his request after the employee told Mr de Oliveira that he did not have the authority.
The indictment sets out a scene where it is claimed Mr de Oliveira walked through bushes and foliage at the edge of Mar-a-Lago, a leisure resort that had been known as the Winter White House, to get to the IT room and meet Mr Nuata.
“What are we going to do,” Mr de Oliveira allegedly asked his co-worker. A lawyer for Mr de Oliveira has declined to comment.
The indictment says the document Mr Trump revealed to the biographers contained possible plans to attack “Country A”, which CNN and other outlets identified as 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 earlier in the day met with Mr Trump’s lawyers over a separate investigation into alleged efforts to overturn the results of the 2020 election.
Mr Trump’s attorneys John Lauro and Todd Blanche met officials at Mr Smith’s office in Washington DC, US media reported.
The former president said earlier this month that he expected to be indicted in that case, but said on Thursday his lawyers received no indication of timing.
“Deranged Jack Smith knows that they have no case and is casting about for any way to salvage their illegal witch hunt,” the statement read.
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 for a hush-money case in which he faces 34 felony counts, he faces civil charges in a defamation case against author E Jean Carroll, and Georgia prosecutors are still weighing whether or not to press charges over an alleged effort overturn the election results there.
