Meet the all-star team of lawyers Robert Mueller has assembled for the Trump-Russia investigation

As the investigation into the Trump campaign's possible ties to Russia gains traction, special counsel Robert Mueller has begun quietly assembling a formidable team of top lawyers and investigators.

Mueller has so far hired 12 people and intends to bring on more, his spokesman Peter Carr told The New York Times.

Only a handful have been named publicly so far, but legal experts and fellow lawyers who have spoken to media in recent days lauded the new hires as a powerhouse team of experienced professionals with sterling credentials who rank among the best in their field.

"That is a great, great team of complete professionals," Kenneth Starr, the former independent counsel who investigated President Bill Clinton, told ABC News.

The members of Mueller's team who've been named have a cumulative 37 years of experience at the FBI and 85 years at the Department of Justice, The Washington Post reported on Friday.

Yet despite the lawyers' resumes and reputations, several members of the team have come under fire for their previous donations to Democrats, prompting some critics to cry foul on the investigation and urge Trump to fire Mueller.

Trump himself has even weighed in:

"You are witnessing the single greatest WITCH HUNT in American political history - led by some very bad and conflicted people!" Trump said Thursday on Twitter.

Here are some of Mueller's new hires: