A "special master" is a court-appointed attorney who can step in to review documents when volumes of evidence are at play in a court case, a legal expert tells Fox News Digital. Former President Trump's legal team continues to press for a special master to review documents seized from his Mar-a-Lago estate.

A special master is an "extension of the authority of the court," according to criminal defense attorney and George Washington University professor Jonathan Turley. 

They are appointed by federal judges, frequently in both civil and criminal cases, typically when there is a lot of evidence to sort through.

In this case, Turley says, a special master would likely be given a mandate by a federal court to perform an independent review of the seized documents from Mar-a-Lago to determine their status, including if any documents were seized outside of the scope of the FBI’s warrant or if any documents are subject to attorney-client privilege. 

TRUMP FBI RAID: DOJ FILES RESPONSE ON POSSIBLE 'SPECIAL MASTER' APPOINTMENT FOR MAR-A-LAGO DOCS

Donald Trump at a rally

Former President Trump at a rally in Arizona. (Brandon Bell)

Judges can appoint any qualified attorney as special master —  for example, a retired senior status judge or retired senior Justice Department official. In this case, the judge will likely look for an attorney with a security clearance, Turley says. The identities of special counsels are made public, he added.

Turley said the federal judge presiding over the Mar-a-Lago case, Aileen M. Cannon of the Southern District of Florida, can make the decision to appoint a special master on her own without consent or request of Trump's legal team or the DOJ, and she has previously indicated "preliminary intent" to do so. 

Turley believes that DOJ’s argument against the Trump team’s "right" to request a special counsel in this case is "rather untenable."

Mar-a-Lago Trump Raid in Palm Beach, Florida

Local law enforcement officers in front of the home of former President Trump at Mar-a-Lago in Palm Beach, Fla., Aug. 9, 2022. (Giorgio Viera/AFP via Getty Images)

The Justice Department argued in it's court filing Tuesday that "the appointment of a special master would impede the government’s ongoing criminal investigation and — if the special master were tasked with reviewing classified documents — would impede the Intelligence Community from conducting its ongoing review of the national security risk that improper storage of these highly sensitive materials may have caused and from identifying measures to rectify or mitigate any damage that improper storage caused.

DOJ FILING ON TRUMP RAID 'SPECIAL MASTER' REQUEST: READ THE DOCUMENT

"This case does not involve any of the types of circumstances that have warranted appointment of a special master to review materials potentially subject to attorney-client privilege."

Trump’s team has a deadline of 8 p.m. ET Wednesday to respond to DOJ ahead of a 1 p.m. ET hearing in Florida Thursday.

FBI Mar-a-Lago raid

The FBI has been criticized for raiding former President Trump's Mar-a-Lago home  (Fox News)

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Fox News' Tyler Olson, Jake Gibson, Brie Stimson and Cecilia Duffy contributed to this report.