A Republican lobbyist pleaded guilty on Friday to running an illegal foreign lobbying campaign, admitting in a plea agreement that he helped steer illicit foreign contributions to President Donald Trump’s inaugural committee.

Sam Patten was charged with violations of the Foreign Agents Registration Act, stemming from undisclosed work on behalf of a Ukrainian political party. The charges were referred to the U.S. Attorney in the District of Columbia by special counsel Robert Mueller, who is investigating Russian influence in the 2016 election. The indictment was first reported by Bloomberg. Shortly after, it was reported that he would plead guilty.

Though charges were not brought by Mueller directly, Patten has agreed to cooperate with the special counsel’s investigation as part of his plea agreement.

That plea agreement focuses on the FARA violations. But Patten also copped to “causing foreign money to be paid to the 2016-17 Presidential Inaugural Committee,” according to the agreement. Patten said he had solicited a U.S. citizen to serve as a “straw purchaser” for an unnamed foreigner to purchase four inauguration tickets at a cost of $50,000. Foreign nationals are prohibited from donating to U.S. political groups such as the inaugural committee, and U.S. citizens are prohibited from knowingly making political contributions in another’s name.

In addition to his current legal troubles, Patten has also been questioned by the Senate Intelligence Committee, according to a source familiar with the interview. That interview was regarding his long-standing relationships with Trump’s one-time campaign chairman Paul Manafort and Konstantin Kilimnik, a Manafort business associate whom Mueller has accused of ties to Russian intelligence.

In his plea agreement, Patten admitted to making false or misleading statements in his testimony before the Intelligence Committee. He did so, the agreement states, in an effort to conceal the inauguration straw donation scheme.

Patten also admitted that he and an unnamed Russian national received more than $1 million to promote the interests of the Ukrainian Opposition Bloc party in the U.S. Prosecutors say the money was routed through a bank account in Cyprus, where Manafort also held shell companies used to illegally hide funds from U.S. tax collectors.

Cyprus accounts were also used to illegally reimburse Patton for the inauguration straw donation scheme.

Patten and the unnamed foreign national, dubbed Foreigner A in the indictment, drafted op-eds in American publications and set up meetings with members of Congress and executive branch officials to advance their clients’ interests on U.S. soil. Such conduct requires registration as a foreign agent with the Justice Department.

Patten registered as a foreign agent for separate work on behalf of a Georgian political party, prosecutors note, suggesting that he was aware of FARA registration requirements.

Patten’s personal website says he has “has worked for multiple political parties and office-holders in Ukraine, exceeding expectations in each instance.” It also boasts work on behalf of clients in George, Kazakhstan, Iraq, Kurdistan, and Russia.

Patten also worked with the company Cambridge Analytica during the 2014 midterm election cycle, helping the company hone its microtargeting tools during that cycle. Years later, Cambridge would work with the Trump campaign, assisting its data operation during the 2016 election.

Patten’s website previously hailed that 2014 work, without naming the company. “Sam worked with one of London’s most innovative strategic communications companies to introduce new technologies and methodologies to U.S. campaigns during the 2014 congressional cycle,” it bragged. “Currently this approach is being adopted by at least one major U.S. presidential candidate.”

That page no longer appears.

Though Friday’s indictment does not identify Foreigner A or the company he formed with Patten, The Daily Beast reported in April that Patten and Kilimnik jointly formed a political consulting firm in Washington in early 2015. Prosecutors say that Patten’s alleged undisclosed foreign lobbying work began that year.

The company, Begemot Ventures International, says it “helps its clients win elections, strengthen political parties, build the right arguments before domestic and international audiences, and achieve better results.”

At the time, Patten denied that the company did any work on U.S. soil. Begemot “is a privately-held, small consulting company that has provided public relations and political strategy advice for clients outside the United States, and [is] not related to the ongoing circus here,” he told The Daily Beast.

Patten did not respond to a request for comment on the indictment.

This story has been updated with additional information