U.S. Rep. Jim Hagedorn, locked in a tough re-election fight and already under scrutiny for his use of taxpayer-funded constituent mail, denied a report Friday that his campaign had rent-free use of a Mankato office in a building owned by a political donor.

In Federal Election Commission reports going back to 2013, Hagedorn's campaign listed a basement suite in the building in question as his campaign headquarters, according to a story published by Politico. But the records show no rent payments for the space.

The building is owned by a Mankato developer who has donated to Hagedorn's bids for office. Failure to disclose free office space as an in-kind donation would likely amount to a violation of federal campaign finance law.

Hagedorn's campaign issued a statement Friday that it only leased a post office box in the building, not office space for the campaign. The campaign did rent "unfinished basement" space in the building to store signs and hold meetings for several months in 2018, for which it paid $100, the statement said.

The statement also said Hagedorn's campaign never rented office space anywhere else.

Hagedorn, a Republican elected two years ago to represent southern Minnesota's First Congressional District, faces a rematch this year with Democrat Dan Feehan. Hagedorn won by less than half a percentage point in 2018, and in recent weeks Feehan has zeroed in on reports of possible ethical lapses by Hagedorn.

"The slow drip of revelations about ethics violations — and potential illegal activity — by Congressman Jim Hagedorn are not only concerning, they're a disservice to Minnesota families," Feehan said in a statement, calling Hagedorn "unfit to serve."

The national Democratic Congressional Campaign Committee has been pouring resources into Feehan's bid this year.

In August, Hagedorn said he had terminated his congressional chief of staff after revelations that his office had spent much of its 2020 budget on mail to constituents. Subsequent reporting suggested that Hagedorn knew more about the mail program than he initially let on.

A Minneapolis attorney filed a complaint over Hagedorn's congressional spending with the independent Office of Congressional Ethics. Upon announcing his former chief's termination, Hagedorn self-reported the situation to the House Ethics Committee. Neither of those entities comment publicly on their inquiries.

Gordon Awsumb, the owner of the Mankato building, told Politico that the rental space in question was not an office location, and that the Hagedorn campaign received no rent-free space. However, the report found a July 2018 tweet from Hagedorn with a picture of the candidate and a large group of volunteers in the basement office, which Hagedorn referred to as "Hagedorn Headquarters in Mankato."

Patrick Condon • 612-673-4413