An attorney for President Trump’s campaign, Jerome M. Marcus, filed a motion Thursday to withdraw his services from a Pennsylvania lawsuit, joining the growing list of Trump staff and advisers to leave their posts after the attack on the U.S. Capitol.

Marcus cited the Pennsylvania Rule of Professional Conduct for his basis of removal from the lawsuit and said Trump had "used the lawyer’s services to perpetrate a crime" in promoting the violent protests that occurred Wednesday.

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The Pennsylvania attorney represented the Trump campaign in a federal case immediately after the election against the Philadelphia County Board of Elections, which sought to prove that Republican poll watchers were not granted access by county officials.

Although Marcus later conceded to U.S. District Court Judge Paul Diamond that the Trump campaign in fact had "a nonzero number of people in the room," meaning that poll watchers had access, according to the Washington Post.

Before denying Trump’s request to stop the count, Diamond asked, "I’m sorry, then what’s your problem?"

The case has not advanced since early November. 

Marcus called Trump’s actions Wednesday "repugnant." He was not alone in condemning the president for stoking anger and inciting violence through his repeated claims of a fraudulent election -- several White House staffers and high-level officials abruptly resigned.

"I can’t stay here," Mick Mulvaney, special envoy to Northern Ireland and President Trump's former chief of staff, told NBC. He resigned with just 13 days left in Trump's presidency.

He was joined by Trump’s deputy national security adviser Matt Pottinger and Ryan Tully, the senior director for European and Russian Affairs at the U.S National Security Council.

White House Deputy Press Secretary Sarah Matthews, East Wing Chief of Staff Stephanie Grisham, and Social Secretary Rickie Niceta were among the first to submit their resignations Wednesday.

Several White House officials cited Trump’s conduct during the mob attack that forced lawmakers to hide in secure shelters, offices, and the upper level in the House chamber as the basis for their resignation. 

Trump waited nearly an hour before telling rioters that had broken into the Capitol to "remain peaceful," and he continued to attack Vice President Mike Pence while he was led away to shelter to protect him from pro-Trump supporters who attempted to stop the certification of the Electoral College results.

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"Mike Pence didn’t have the courage to do what should have been done to protect our Country and our Constitution, giving States a chance to certify a corrected set of facts, not the fraudulent or inaccurate ones which they were asked to previously certify," Trump wrote in a tweet that has since been taken down by Twitter before the social media platform froze his account. "USA demands the truth!"

Trump released a video asking the mob to "go home" but proceeded to propagate his claims that the election was stolen from him and praised the violent crowd telling them: "We love you," and "You're very special." 

Former Attorney General William Barr, also condemned the rioters and the president as well, calling his conduct a "betrayal."

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"Orchestrating a mob to pressure Congress is inexcusable," Barr said in a statement to Fox News. "The President’s conduct yesterday was a betrayal of his office and supporters."

Marcus could not be immediately reached for comment.

John Roberts contributed to this report.