Congressional Republicans, not President Donald Trump, should look into removing former FBI Director Robert Mueller as special counsel investigating Russian interference and collusion in the 2016 election because he has already hired "bad people" for his staff, ex-House Speaker Newt Gingrich said Tuesday.

"I don't think Trump should do anything, but the congressional Republicans ought to look into it," Gingrich told ABC's "Good Morning America" anchor George Stephanopoulos.

"[Mueller's] first four hires were all Democrats."

One of Mueller's hires, Gingrich continued, had "worked for the Clinton Foundation, one of them [in] two cases, deliberately hid evidence from the defense, one of which was repudiated by 9-1 by the Supreme Court. These are bad people."

"Bad people," Stephanopoulos repeated.

"Bad people," Gingrich confirmed. "I mean, these are people who are going to be after Trump."

So far, Mueller has hired several staffers, including Deputy Solicitor General Michael Dreeben, former Deputy Assistant Attorney General Jeannie Rhee; Aaron Zebley, Mueller's chief of staff when he was FBI director; and James Quarles, a former assistant special prosecutor on the Watergate Special Prosecution Force, CBS News reports.

Dreeben donated $250 to then-presidential candidate Sen. Barack Obama in 2007 and in 2008, and he gave $1,000 to Hillary Clinton in 2006, CBS reports, quoting Open Secrets.

Rhee, meanwhile, has donated thousands to Democrats, including Obama, Clinton, Sen. Chris Van Hollen and Sen. Mark Udall, among others.

Quarles' donations include money to a long list of Democrats, including Obama, Clinton, John Kerry, Al Gore, Sen. Charles Schumer, Sen. Ed Markey, Sen. Bob Menendez, Sen. Ron Wyden, Rep. John Spratt, former Sen. Mary Landrieu and Sen. Chris Van Hollen, according to CBS.

He has also given money, however, to two Republicans — Rep. Jason Chaffetz and former Virginia Gov. George Allen.

Zebley has not donated politically.

Meanwhile, Ken Starr, the special counsel in charge of investigating former President Bill Clinton and the Whitewater scandal, hired no Republicans in his first wave, Gingrich noted.

Starr, though, has commented that Mueller is pulling together a team of "complete professionals," said Stephanopoulos, but Gingrich said he does not agree with that.

"Ken Starr and I live in two different universes then," said Gingrich. "When the first four people you hire all donated to the Democrats and Hillary in one case . . . I am very dubious about the team."

Starr had also given political contributions to Republicans, Stephanopoulos argued, but Gingrich said now, "we're in a different world."

"If you look at the intensity of where we are right now, whether it is somebody holding up the bleeding head of the president or a New York play showing the assassination of the president, we are in a period where if people think this is going to be a neutral, professional investigation, I think they're delusional," said Gingrich.

Stephanopoulos pointed out that Gingrich himself had praised Mueller, through a tweet on May 17, as a "superb choice" as special counsel.

Gingrich said he changed his mind when former FBI Director James Comey testified to the Senate Intelligence Committee last week, in an "arrogant statement," that he "felt he had the right to leak to The New York Times" in order to spur a demand for a special counsel.

"A special counsel that happens to be his best friend," Gingrich said.