President Trump’s lawyers and aides are scouring the professional and political backgrounds of investigators hired by the special counsel Robert S. Mueller III, looking for conflicts of interest they could use to discredit the investigation — or even build a case to fire Mr. Mueller or get some members of his team recused, according to three people with knowledge of the research effort.
The search for potential conflicts is wide-ranging. It includes scrutinizing donations to Democratic candidates, investigators’ past clients and Mr. Mueller’s relationship with James B. Comey, whose firing as F.B.I. director is part of the special counsel’s investigation.
The effort to investigate the investigators is another sign of a looming showdown between Mr. Trump and Mr. Mueller, who has assembled a team of high-powered prosecutors and agents to examine whether any of Mr. Trump’s advisers aided Russia’s campaign to disrupt last year’s presidential election.
Some of the investigators have vast experience prosecuting financial malfeasance, and the prospect that Mr. Mueller’s inquiry could evolve into an expansive examination of Mr. Trump’s financial history has stoked fears among the president’s aides. Both Mr. Trump and his aides have said publicly they are watching closely to ensure Mr. Mueller’s investigation remains narrowly focused on last year’s election.
During an interview with The New York Times on Wednesday, Mr. Trump said he was aware that members of Mr. Mueller’s team had potential conflicts of interest and would make the information available “at some point.”
Mr. Trump also said Mr. Mueller would be going outside his mandate if he begins investigating matters unrelated to Russia, like the president’s personal finances. Mr. Trump repeatedly declined to say what he might do if Mr. Mueller appeared to exceed that mandate. But his comments to The Times represented a clear message to Mr. Mueller.
“The president’s making clear that the special counsel should not move outside the scope of the investigation,” Sarah Huckabee Sanders, a White House spokeswoman, said during a news briefing on Thursday.
Joshua Stueve, a spokesman for the special counsel, declined to comment.
For weeks, Republicans have publicly identified what they see as potential conflicts among Mr. Mueller’s team of more than a dozen investigators. In particular, they have cited thousands of dollars of political donations to Democrats, including former President Barack Obama, made by Andrew Weissmann, a former senior Justice Department official who has expertise in fraud and other financial crimes. News reports have revealed similar donations by other members of Mr. Mueller’s team, which Mr. Trump’s allies have cited as evidence of political bias. Another lawyer Mr. Mueller has hired, Jeannie Rhee, represented the Clinton Foundation.
To seek a recusal, Mr. Trump’s lawyers can argue their case to Mr. Mueller or his boss, Deputy Attorney General Rod J. Rosenstein. The Justice Department has explicit rules about what constitutes a conflict of interest. Prosecutors may not participate in investigations if they have “a personal or political relationship” with the subject of the case. Making campaign donations is not included on the list of things that would create a “political relationship.”
The examination of Mr. Mueller’s investigators reflects deep concerns among the president’s aides that Mr. Mueller will mount a wide-ranging investigation in the mold of the inquiry conducted by the independent counsel Kenneth W. Starr during the 1990s. Mr. Starr’s investigation into President Bill Clinton began by reviewing an Arkansas land deal and concluded several years later with the president’s impeachment over a lie about a sexual affair.
By building files on Mr. Mueller’s team, the Trump administration is following in the footsteps of the Clinton White House, which openly challenged Mr. Starr and criticized what Mr. Clinton’s aides saw as a political witch hunt.