Justice Department has used a federal grand jury for the investigation of Mar-a-Lago documents from former U.S. President Donald Trump.

Forbes reported that the grand jury has assembled and issued at least one subpoena in the Mar-a-Lago documents probe, implying that the investigation is gaining momentum.

Prosecutors recently subpoenaed the National Archives and Records Administration for boxes of documents shipped from the White House to Mar-a-Lago, according to two sources familiar with the matter.

One source noted that some investigators had asked some former Trump White House aides about the boxes and how they were prepared.

Another person said that investigators were still making interview requests of those involved, according to a Washington Post report.

A Justice Department spokesman did not comment on the ongoing probe.

Trump spokesman Taylor Budowich said that the former president "consistently handled all documents" in compliance with applicable law and regulations.

He added that to second-guess that clear fact are "politically motivated and misguided."

READ NEXT: National Archives Asks DOJ to Investigate Donald Trump for Hoarding Classified Documents to Mar-a-Lago

Mar-a-Lago Documents

National Archives officials had earlier confirmed in a letter to the House Oversight Committee that some of the documents found in Mar-a-Lago were marked "classified," adding that they had referred the issue to the Justice Department, according to an ABC News report.

Trump reportedly took 15 boxes of records with him to Mar-a-Lago after leaving office, which is a violation of the Presidential Records Act.

It was not clear whether Trump was aware that he may have been breaking the law by moving the documents.

In addition, some White House records turned over to the January 6 committee were torn up and had to be taped back together.

An upcoming book from New York Times reporter Maggie Haberman also alleged that the White House toilets were clogged with documents on several occasions while Trump was in office.

Trump had called the claims of clogging the toilet with documents as "categorically untrue."

National Archives Taking Mar-a-Lago Documents

In February, the National Archives took the Mar-a-Lago documents while confirming that they sent the matter to the Justice Department.

Trump commented on the matter. In an Associated Press News report, the former president said that the Archives department did not find "anything," and those were given upon request.

The former president also denied reports about his administration's "tenuous relationship with the National Archives."

Trump's lawyers said that they are still searching for more presidential records that belong to the National Archives.

Archivists said in their letter to the House Committee on Oversight and Reform that certain social media records were not preserved by the Trump administration.

In addition, the agency learned that White House staff frequently conducted official business using unofficial messaging accounts and personal phones.

The staff did not copy or forward their official messaging counts, which was required by the Presidential Records Act.

Additional paper records had also been torn up by the former president had been transferred to the agency.

Lawmakers are also looking for information about the contents of the boxes that were recovered from Mar-a-Lago.

READ MORE: Donald Trump's Pardon Talk Sparks Major Concern Among Republicans: "He'll Do It All Again!"

This article is owned by Latin Post.

Written by: Mary Webber

WATCH: National Archives confirm some classified documents were found at Mar-a-Lago - from ABC News