RALEIGH, N.C. — The Republican candidate in North Carolina’s unresolved congressional race has acknowledged owing $34,310 to a political consultant subpoenaed in a ballot fraud probe, according to a federal campaign filing that refers to work at the heart of the investigation.

The Mark Harris campaign listed its debt to the Red Dome Group in a late Thursday filing with the Federal Election Commission. The form said the nature of the debt included “Reimbursement Payment for Bladen Absentee” and “Reimbursement Door to Door.”

Bladen County’s absentee ballots are at the center of a fraud probe that has prompted the North Carolina Elections Board to refuse to certify Harris as the winner over Democrat Dan McCready. The board cited allegations of “irregularities and concerted fraudulent activities” involving mail-in ballots, and subpoenaed both the Harris campaign and Red Dome for documents.

The board could order a new election after meeting later this month to consider the evidence. For now, the vote count remains unofficial, with Harris leading McCready by 905 votes.

Some Bladen County voters have said strangers came to their homes to collect their absentee ballots, whether or not they had been fully completed or sealed in an envelope to keep them from being altered, according to affidavits offered by the state Democratic Party. State law allows only a family member or legal guardian to drop off absentee ballots for a voter.

Red Dome hired Bladen County contractor McCrae Dowless, whose criminal record includes prison time in 1995 for felony fraud and a conviction for felony perjury in 1992.

According to documents released by the elections board, Dowless seems to have collected the most absentee ballot request forms in Bladen County this fall. A copy of the Bladen election board’s log book shows Dowless turned in well over 500 applications.

The FEC report also lists two other debts totaling nearly $20,000 to Red Dome for digital advertising, robocalls and mailings for Harris. The filing says those mailings were in Robeson County, another area where the state board has sought information as part of its probe. The details were part of a wide-ranging post-election report on the campaign’s finances.

McCready, expressing outrage over what he called a shameful attack on democracy, withdrew his concession in a video released late Thursday. He’s demanding that Harris explain what he knows about the absentee ballot allegations.

“He hired a criminal who was under investigation for ballot fraud to do his absentee ballot work, and it looks like he got what he paid for,” McCready told CNN on Friday.

Harris didn’t respond to a message seeking comment late Thursday. He issued a statement last week saying he supports a voter fraud investigation, but that the race should be certified in the meantime because there didn’t appear to be enough questioned votes to erase his lead. His campaign lawyer said this week the organization wasn’t aware of any illegal conduct during the race.

Dowless declined comment when visited by an Associated Press reporter this week at his home, and didn’t immediately respond to a phone message Friday. The head of the Red Dome Group, Andy Yates, also didn’t immediately respond to an e-mail Friday.