She and her husband, Brian Foley, pleaded guilty last month to related charges, bringing Mr. Rowland under scrutiny when prosecutors said he was one of four unindicted co-conspirators in the case. Ms. Wilson-Foley, who lost the Republican primary, and her husband each face up to a year in prison and fines of up to $100,000.

One of her opponents was a former F.B.I. agent, Mike Clark, who had been an investigator on the case that forced Mr. Rowland to resign as governor. Mr. Rowland approached the Foleys in 2011, according to emails cited by prosecutors in the case against Ms. Wilson-Foley.

Image Former Gov. John G. Rowland of Connecticut. Credit Jessica Hill/Associated Press

He said he wanted to replace another political consultant the campaign had hired. But Ms. Wilson-Foley was concerned that if word got out about his role in the campaign, the fallout could hurt her hopes of winning.

The authorities say Mr. Rowland used Mr. Foley’s nursing home company as a cover for the campaign work. They say a fictitious contract was drawn up that appeared to be an agreement between Mr. Rowland and a lawyer who worked for the nursing home company. But prosecutors said Mr. Foley made regular payments to Mr. Rowland, routing the money from a real estate company to the lawyer and then on to Mr. Rowland.

The indictment said Mr. Rowland was paid about $35,000 for his work on Ms. Wilson-Foley’s campaign for the House seat, which he once held. Prosecutors maintain that the money amounted to a campaign contribution, but that it was not reported to the Federal Election Commission, in violation of federal election laws.