North Carolina election officials have subpoenaed the campaign of the GOP candidate who may see his unofficial victory in a U.S. House race tossed out after claims of a potential absentee ballot fraud scheme, the Washington Post reported.

Republican Mark Harris’ campaign was subpoenaed on Monday, according the Post, while Red Dome Group, a consulting firm Harris (pictured above) hired, is expected to be subpoenaed in the days to come. State election officials and other investigators are probing anomalies in the mail-in ballot counts in the district, where the numbers were particularly outside the norm in Bladen County and Robeson County.

Bladen County reported the highest mail-in ballot return rate in the state, and Harris won 61 percent of those ballots, despite only 19 percent of them having been sent in by registered Republicans. During his primary against incumbent Republican Rep. Robert Pittenger, Harris claimed 96 percent of the mail-in ballots in Bladen County— a rate much higher than his general performance in the county.

The North Carolina State Board of Elections last week declined to certify Harris’ unofficial victory — where his lead over Democrat Dan McCready is just 905 votes — and voted to hold a hearing later this month on any potential evidence of fraud turned up in its investigation into the irregularities. The board could vote to call a whole new election.

Scrutiny is focused on the role that a local operative Leslie McCrae Dowless played for Harris campaign. Dowless — who is a local elected official and has worked for candidates of both parties — has in the past been accused of shady campaign tactics.

For Harris, Dowless managed an absentee ballot collection program, his ex-friend and the owner of the building Dowless worked for told Washington Post. North Carolina allows only voters themselves or designated relatives to return absentee ballots. Dowless denied wrongdoing to the Charlotte Observer, but didn’t respond to the Washington Post’s inquiries.

Jeff Smith, the ex-friend who said he had a falling out with Dowless after the primary, was with a Washington Post reporter when a state board of elections investigator called him to ask him about Dowless. With the Post reporter present, he retold his story about Dowless to the investigator on the phone.