SALT LAKE CITY — Sen. Mike Lee said Thursday that neither he nor anyone on his campaign knew about $50,000 in contributions being made in other people's names as alleged in a complaint filed with the Federal Election Commission.

The complaint from the left-leaning Alliance for a Better Utah asks the FEC to investigate allegations that Lee, R-Utah, accepted so-called "straw donations" during his 2010 Senate race and should have reported the short sale of his Alpine home.

"If anyone used straw donors to contribute to my campaign, I don't support that. I wholeheartedly reject that," the Utah Republican told KSL Newsradio's "Doug Wright Show." "And if that did happen, that happened unbeknownst to me. I have absolutely no knowledge of that happening."

He said if someone was using straw donors to contribute to his campaign, neither he nor anyone on his campaign team knew.

"None of us had any idea about it," Lee said.

Jeremy Johnson, the person alleged to have engaged in that activity, a violation of federal election law, "is someone who did himself donate to my campaign. He is also someone I never met," Lee said.

The allegation surfaced in a recently released search warrant affidavit in the ongoing criminal investigation into former attorneys general Mark Shurtleff and his successor, John Swallow, by the FBI, the Salt Lake County district attorney and the Davis County attorney.

According to the affidavit, Johnson said Swallow told him he could contribute $100,000 — well above the $2,500 federal limit — to Shurtleff's brief Senate campaign by giving the money to other people to donate.

Johnson also reportedly said Swallow told him he could do the same thing for Lee's campaign, and he did so in the amount of $50,000.

Shurtleff had said he had no knowledge of Swallow telling Johnson to contribute through other people. Swallow's attorney, Rod Snow, said Swallow "believed the individuals who were making contributions were using their own funds."

Alliance for a Better Utah spokesman Isaac Holyoak said Lee is responsible for his campaign, regardless of what he may or may not know.

"Legally, ignorance can be a defense. As far as publicly, as far as professionally, as far as the citizens of Utah are concerned, it's not a defense because he's ultimately responsible," Holyoak said. "This is his campaign. He's running the show."

Holyoak said the complaint includes allegations that Lee in effect accepted improper campaign donations from the company that took a loss in the short sale of Lee's home and the contributor who purchased it and leased Lee a new house.

Email: lisa@deseretnews.com, Twitter: DNewsPolitics