Nine House Republicans on Monday sent a letter asking Deputy Attorney General Rod Rosenstein to list the names of everyone “past and present” who has worked on special counsel Robert Mueller’s investigation into Russian collusion with the Trump campaign.

“Please provide Congress with the names of everyone who has served — past and present — on Robert Mueller’s special counsel investigation,” the lawmakers said in the letter. “Congress’s constitutional oversight gives us the responsibility to know who is involved — and whether other members of Mr. Mueller’s team harbor political biases and have conflicts of interest. These investigators endangers our ability to uphold justice.”

Justice Department Inspector General Michael Horowitz dinged five FBI employees for their anti-Trump bias in a recent report. Three of these employees — Peter Strzok, Lisa Page and Kevin Clinesmith — ended up on Mr. Mueller’s team.

The lawmakers said they were “disturbed” that these individuals were chosen for Mr. Mueller’s team.

“We know that these biases were shared among multiple people at the FBI and could easily be uncovered by Mr. Mueller with simple vetting,” the lawmakers said. “These individuals should not have been given an opportunity to influence — directly or indirectly — this special counsel investigation.”

The letter also asks Mr. Rosenstein if there are more politically biased investigators on Muller’s team.

Mr. Strzok was removed from Mr. Mueller’s team last year after Mr. Horowitz had uncovered the anti-Trump texts he sent his lover, Ms. Page. She also left the special counsel’s office before the messages disparaging the president were discovered.

Rep. Mark Meadows, North Carolina Republican, said last week Mr. Clinesmith is the FBI employee named in the inspector general’s report as “FBI Attorney 2.” Mr. Horowitz included in his report messages from Attorney 2, which express dismay over Mr. Trump’s election.

He left the Meuller probe earlier this year.

The nine Republicans are Reps. Andy Biggs of Arizona, Scott DesJarlais of Tennessee, Jeff Duncan of South Carolina, Matt Gaetz of Florida, Paul Gosar of Arizona, Andy Harris of Maryland and Jody Hice of Georgia.