It concerns the part that deals with the incoming president's attempts to have the result of the 2020 presidential election declared invalid.
The message comes the day after a federal judge temporarily stopped the publication of Jack Smith's investigation into Trump.
It is still unclear when the information can be released.
The rest of the investigation, which has focused on Trump's handling of classified documents stored at the Mar-a-Lago residence in Florida after he left the White House, will, however, continue to remain secret.
The Justice Department's message means that the likelihood decreases that the investigation into the classified documents will ever be released, as it is unlikely that it will be released by a department under the leadership of President Trump.
Trump has consistently denied doing anything wrong and has directed fierce criticism at Jack Smith.
