Trump's legal team has been probing the backgrounds of investigators on the case as well as checking for any potential conflicts of interest that could foil Mueller's inquiry, the Washington Post and New York Times said in separate reports, each citing anonymous sources.
These research efforts may also be aimed at firing Mueller or getting some members of his team recused, the New York Times said. The president told the Times on Wednesday that members of Mueller's team had potential conflicts of interest, adding that he would make the information available "at some point."
Trump has also asked advisers about the president's pardoning authority, specifically in relation to aides, family members and himself, the Washington Post reported. Mark Corallo, a spokesman for Trump's external legal team, also resigned on Thursday, the Post added.
Tasked with examining alleged Russian interference in the 2016 U.S. presidential election, Mueller has been inspecting the president's business dealings as well as those of his family and associates.