Special Counsel Robert Mueller is the only known Republican on the team investigating Russian meddling and potential collusion with Trump campaign associates during the 2016 presidential election, according to a review by Fox News.

The majority of the 17 publicly confirmed attorneys on Mueller’s team are registered Democrats -- and others have made Democratic political donations.

That donation history has long fueled concerns from Trump-aligned Republicans about potential bias in the unit. While any team of investigators is bound to have members with their own political views, the Democratic-leaning makeup of this particular team was underscored when The Daily Caller reported that no registered Republicans were working under Mueller.

There appear to be only two asterisks to that stat: The Caller reported that Mueller lawyer Zainab Ahmad was registered as a Republican at the age of 18 but has since changed her registration status to unaffiliated; and Mueller himself was known to be a Republican when appointed to lead the FBI in 2001 by then-President George W. Bush. Mueller's current party registration is not clear.

A review by Fox News shows that of the 17 attorneys, at least nine attorneys are registered Democrats. Others have registered with “no party declared,” or their registration was not known.

And a review of political donation records shows at least 10 of Mueller’s attorneys -- including some of the registered Democrats -- have donated to Democratic candidates and causes like former President Barack Obama, Hillary Clinton, Sen. Kirsten Gillibrand, D-N.Y., and the Democratic National Committee.

Mueller's team has been particularly active in recent days, securing a major indictment against more than a dozen Russian nationals last week and on Thursday bringing new charges against Trump campaign officials Paul Manafort and Rick Gates.

The pace is sure to bring new scrutiny to the team itself.

According to Mueller's office, his team includes 17 attorneys: Ahmad, Greg Andres, Lawrence Rush Atkinson, Ryan Dickey, Michael Dreeben, Kyle Freeny, Andrew Goldstein, Adam Jed, Scott Meisler, Elizabeth Prelogar, James Quarles, Jeannie Rhee, Brian Richardson, Brandon Van Grack, Andrew Weissmann, Aaron Zebley, and Aaron Zelinksky.

Quarles, whose voter registration is unknown, is a former partner at WilmerHale. He donated over $7,000 to Obama in the last decade, and $2,700 to Clinton’s 2016 presidential campaign. He did, however, also donate $2,500 to Jason Chaffetz, the former Republican congressman from Utah, in 2015.

Rhee, a registered Democrat and former partner at WilmerHale, also donated a total of $5,400 to Clinton. Rhee donated a combined $4,800 to Obama in 2008 and 2011, along with smaller contributions to the DNC and Democrats running for Congress.

MUELLER PROBE: MEET THE LAWYERS WHO GAVE $$ TO HILLARY, NOW INVESTIGATING TEAM TRUMP

Weissmann, a registered Democrat who served as general counsel at the FBI and was an assistant U.S. attorney for the Eastern District of New York, donated a combined $2,300 to Obama’s campaign in 2008 -- and in 2006, contributed at least $2,000 to the DNC.

Andres, a registered Democrat and a former partner at Davis Polk and former assistant U.S. attorney for the Eastern District of New York, donated at least $2,700 to Gillibrand in 2017, along with smaller donations to other Democratic candidates.

Dreeben, whose voter registration is unknown, is an appellate attorney for the Office of the Solicitor General. He donated $1,000 to Clinton in 2006, and a combined $1,000 to Obama in 2007 and 2008.

While Trump allies called into question the Democratic donations of Mueller's attorneys last year, there has been a renewed focus on the team after the release of anti-Trump text messages from two former members -- FBI officials Peter Strzok and Lisa Page, who were romantically involved.

READ FBI'S STRZOK, PAGE TEXTS ABOUT TRUMP

Despite the scrutiny Mueller has faced throughout the probe, Justice Department policy “prohibits the consideration of political affiliation in personnel matters involving career employees” –meaning, an attorney on detail has a right to their own political beliefs.

“All employees and applicants for employment should receive fair and equitable treatment in all aspects of personnel management without regard to political affiliation,” U.S.C. 2301 (b) (2) reads.

“Identifying candidates as ‘liberal’ or ‘conservative’ by the activities or organizations with which they are affiliated can be used as a proxy for political affiliation and thus can violate CSRA’s prohibition,” according to the Justice Department rules. “Using ideological affiliation can violate the requirement that the government use hiring practices for career positions that ensure it identifies the best qualified applicants through fair and open competition.”