Washington (CNN) Three members of the legal team known to have been hired so far by special counsel Robert Mueller to handle the Russia investigation have given political donations almost exclusively to Democrats, according to a CNN analysis of Federal Election Commission records.

More than half of the more than $56,000 came from just one lawyer and more than half of it was donated before the 2016 election, but two of the lawyers gave the maximum $2,700 donation to Hillary Clinton last year.

Over the weekend, news outlets including CNN identified five attorneys that Mueller has already brought on board to help investigate potential collusion between associates of President Donald Trump's campaign and Russia.

The group includes seasoned attorneys who worked on cases ranging from Watergate to the Enron fraud scandal and have represented major American companies in court. While only five attorneys have been publicly identified as working on the Russia probe, there could be more on Mueller's team.

Three of the five lawyers have donations in FEC records. They gave overwhelmingly to Democrats, totaling more than $53,000 since 1988. More than half of the donations came from just one of the lawyers, James Quarles, whom Mueller brought over from his old firm, WilmerHale.

Quarles has given nearly $33,000 to political campaigns over the years. He gave money to Democratic presidential candidates Michael Dukakis, Al Gore, John Kerry, Barack Obama and Hillary Clinton. In addition, Quarles gave more than $10,000 to help Democrats get elected to the House and another $10,000 on the Senate side, including money to Senate Minority Leader Chuck Schumer.

But Quarles is also the only lawyer among Mueller's team for which records were available who ever donated to Republicans. He gave $2,500 to Utah Rep. Jason Chaffetz in 2015 and gave $250 to then-Sen. George Allen of Virginia in 2005.

Only about 30% of the donations were for elections in 2016. But Quarles and Jeannie Rhee, who also left WilmerHale to work on the Russia probe, gave the maximum contribution of $2,700 to Clinton's campaign last year.

Rhee was the second-largest donor among Mueller's known team. Rhee has donated more than $16,000 since 2008, all to Democrats. She maxed out to the Clinton campaign in 2016 and 2015, totaling $5,400. She also gave a total of $7,300 to Obama's two presidential campaigns. She has already received attention for representing the Clinton Foundation in a racketeering lawsuit brought by a conservative advocacy group, and also represented Clinton herself in a lawsuit seeking access to her private emails.

Mueller, who was appointed to be FBI director by Republican President George W. Bush, also hired Andrew Weissmann to join his team. Weissmann, who led the Enron investigation, previously gave $2,300 to Obama's first presidential campaign in 2008 and $2,000 to the Democratic National Committee in 2006, the same year Democrats won control of Congress.

FEC records do not show any donations by Weissman in the 2016 election cycle.

There also are no FEC records for Aaron Zebley, who left WilmerHale to work on the Russia investigation. Zebley once represented former Hillary Clinton aide Justin Cooper, who helped manager her private email server.

Deputy Solicitor General Michael Dreeben has also joined Mueller's team. While there is a Michael Dreeben in the FEC database, who is identified as a deputy solicitor with the Justice Department and who gave $1000 to Hillary Clinton's senate campaign in 2006, a spokesman for Mueller's team told CNN late Monday that that is not the same person.

Former House Speaker Newt Gingrich, who endorsed Trump and was on his vice-presidential shortlist, suggested Monday that Mueller's team can't be impartial because of their past donations.

"Republicans are delusional if they think the special counsel is going to be fair," Gingrich tweeted, reversing his previous praise for Mueller. "Look who he is hiring. Check FEC reports. Time to rethink."

Deputy Attorney General Rod Rosenstein, who appointed Mueller as special counsel, told senators on Tuesday that he doesn't see any problems with the political donations from some members of Mueller's legal team.

Asked by Sen. Lindsey Graham whether political donations should prevent attorneys from working on the investigation, Rosenstein replied, "no, senator, it is not a disqualification. It is not."

Even with the questions about Mueller's team, former independent counsel Kenneth Starr, who led investigations into President Bill Clinton in the 1990s, said he has confidence in the team.

"He has his head down, he's doing his job, he's assembled a fantastic team," Starr said Monday to ABC News . "That is a great, great team of complete professionals, so let's let him do his job."

There aren't any records of political donations from Mueller himself. A spokesman for Mueller declined to comment Monday afternoon about the political donations from his legal team and the criticism some of the team were partisan.

Mueller received near-universal praise since taking over the investigation on May 17. But with the investigation ramping up, Trump's legal team is looking for new ways to go on the offensive. In a TV appearance over the weekend, one of Trump's lawyers wouldn't rule out the possibility of firing Mueller.

CORRECTION: This story has been updated to reflect the Mueller team spokesman telling CNN that the Dreeben identified in FEC records as a deputy solicitor with the Justice Department who donated to Clinton in 2006 is not the same person working for Mueller.