Former special counsel Robert Mueller avoided questions Wednesday on the political bias of his staff and how that bias may have affected his nearly two-year investigation into Russian interference in the 2016 presidential election.

During testimony in front of the House Judiciary Committee, Mueller told Republican North Dakota Rep. Kelly Armstrong that he did not vet the political leanings of his staff, which included prominent attorney Andrew Weissmann. Weissmann attended Hillary Clinton’s election night party in 2016. (RELATED: Amash Reacts To Mueller Statement: ‘The Ball Is In Our Court’)

“I don’t know when I found that out,” Mueller said of the revelation that Weissmann attended Clinton’s election night party.

Armstrong also pointed out Weissmann’s previous praise of former acting Attorney General Sally Yates, who was fired after refusing to defend President Donald Trump’s travel ban in court.

“January 30th, 2017 Weissmann wrote an email to Attorney general Yates stating I’m so proud and in awe regarding her disobeying a direct order from the president. Did he disclose that email to you before he joined the team. Isn’t that a conflict of interest?” Armstrong asked.

“Not going to talk about that,” Mueller said.

After Armstrong pointed out that six of Mueller’s lawyers donated thousands to Clinton’s presidential campaign, Mueller said he did not consider the political leanings of his team members.

” We strive to hire those individuals that could do the job. I have been in this business for 25 years. I haven’t had an occasion to ask somebody about their political affiliation,” Mueller said. “It is not done. I care about the capability of the individuals that do the job and do the job quickly and seriously and with integrity.”