A Republican operative pleaded guilty to a federal crime Tuesday for his involvement in political action committees that prosecutors say defrauded their donors.

Scott B. Mackenzie’s plea to filing false reports with the Federal Election Commission in federal court in Alexandria comes weeks after fellow operative Kelley Rogers admitted broader donor fraud.

Mackenzie, who worked on the political campaigns of Ronald Reagan, Jack Kemp and Patrick J. Buchanan, agreed to pay $172,000 in restitution. The 66-year-old Arlington resident will be sentenced on Feb. 21 and could face up to five years in prison; he declined to comment after the plea.

Both men were involved with the political consulting firm Strategic Campaign Group, which took money from a network of PACs that included Conservative StrikeForce, Conservative Majority Fund and Tea Party Majority Fund. Mackenzie served as treasurer of those and about four dozen other PACs, he said in court.

The committees, according to court documents, spent most of their money on overhead and little on the candidates they claimed to be helping. Instead, funds went to their firms and associates, including $32,500 to a woman in Winchester, Va., who shared a bank account with Mackenzie and pretended to be doing data entry for his groups, the documents state.

The woman, whom The Washington Post is not identifying because she has not been charged, did not return a request for comment.

Mackenzie also used the woman as a conduit for illegal contributions in 2012 and 2015, according to the plea, including corporate contributions and individual contributions over the legal limits. Although the candidates were not named, FEC records indicate that they were U.S. House candidates Cherilyn Eagar of Utah and Brent Waltz of Indiana.

Mackenzie and Rogers were both defendants in a lawsuit Ken Cuccinelli II filed in 2014 against groups that claimed to raise money for his Virginia gubernatorial campaign the previous year. Conservative StrikeForce agreed in 2015 to pay Cuccinelli, now acting head of U.S. Citizenship and Immigration Services, $85,000 to settle the lawsuit.

Mackenzie admitted he used at least $172,200 from small donors to pay legal fees related to that case.

He has also been involved in half a dozen settlements with various campaigns through the FEC. As part of his plea, he must notify clients, vendors and any committee he is involved with about the case. His attorney Andrea Moseley said in court that “there isn’t much going on right now” for him professionally.

Strategic Campaign Group’s Annapolis headquarters was searched by the FBI in 2017.

Policing unscrupulous political action committees has been a challenge for the FEC. A single consultant can run a PAC, unlike a nonprofit group. And unlike a campaign, a PAC faces few limitations in how funds can be spent.