BLADENBORO, N.C. — When Republican Rep. Robert Pittenger lost his primary by a narrow margin in May, he suspected something was amiss.

The congressman turned to a group of friends and family who had gathered with him on election night at a steakhouse near Charlotte, North Carolina, and blamed the “ballot stuffers in Bladen,” according to three people at the gathering.

Pittenger’s concern stemmed from the vote tallies in rural Bladen County, North Carolina, where his challenger, a pastor from the Charlotte suburbs named Mark Harris, had won 437 absentee mail-in votes. Pittenger, a three-term incumbent, had received just 17.

In the days immediately after the race, aides to Pittenger told the executive director of the North Carolina Republican Party and a regional political director for the National Republican Congressional Committee that they believed fraud had occurred, according to people familiar with their discussions.

DENIAL FROM NATIONAL GROUP

Republican officials did little to scrutinize the results, instead turning their attention to Harris’ general-election campaign against a well-funded Democratic opponent, the people said.

Their accounts provide the first indication that state and national Republican officials received early warnings about voting irregularities in North Carolina’s 9th Congressional District, now the subject of multiple criminal probes.

A spokesman for the NRCC denied that Pittenger’s campaign raised the possibility of fraud in the primary.

Allegations of fraud in November’s general election have now put the outcome of the 9th Congressional District race in limbo. State investigators are examining the activities of a political operative named Leslie McCrae Dowless, who ran a get-out-the-vote effort for the Harris campaign during the primary and general elections.

While the investigation continues, the elections board has declined to certify the 9th District race, in which Harris leads Democrat Dan McCready by 905 votes, according to unofficial results.

On Thursday, McCready told television station WSOC that he was withdrawing his concession and accused Harris of bankrolling “criminal activity.”

Dowless, who has worked on political campaigns in Bladen for at least a decade, touts his ability to mobilize voters to cast ballots by mail, according to people who know him. He has been under scrutiny by state officials since 2016, when allegations surfaced about illegal ballot harvesting in that year’s campaigns, leading to a public hearing.

‘CURSORY LOOK’ AT VOTE TOTALS

Dowless, who told the Charlotte Observer that he did not commit any wrongdoing, declined to comment Thursday. “I’m just not giving any comment at this time,” he told reporters and photographers in front of his house in Bladenboro, adding, “No disrespect to anybody.”

Pittenger said Dowless tried to sell him his services in 2016 but that he declined to hire the operative.

“I just knew I didn’t want to be involved with him,” Pittenger said. “Dowless’ efforts were widely known, and we did share our concerns with several people,” declining to elaborate on who he spoke to or what he said.

Since reports of irregularities in the 9th District emerged last month, Republican leaders in the state – including Dallas Woodhouse, the state Republican executive director – initially played down concerns that laws were broken. They repeatedly cast the situation in political terms, asserting that any voting irregularities were not widespread enough to change the outcome of the election.

In recent days, amid mounting allegations of a ballot-harvesting operation, state Republicans have shifted their rhetoric. Woodhouse told The Post on Thursday that if the state elections board can “show a substantial likelihood” that possible fraud could have changed the outcome of November’s vote, “then we fully would support a new election.”

In an interview this week, Woodhouse initially said he did not recall fielding complaints from Pittenger aides of possible fraud after the primary. But he called back a few moments later to say that he did remember hearing of anomalies – and took “a cursory look at the end of that race at the vote totals.”

He recalled concluding that Harris had won the overall vote with a strong showing from evangelical voters, but he said: “We did not look real specifically at absentee ballots.”

CAMPAIGN AIDES ‘ALL UPSET’

“If somebody said something about the absentee ballots, it is just very possible that it didn’t register with us,” Woodhouse said. “We had a lot of campaigns and a lot of people expressing concerns at the end of the election, and we were trying to quickly move on to the general election.”

NRCC spokesman Matt Gorman denied that anyone affiliated with the Pittenger campaign brought up possible fraud to anyone at the committee, including Tyler Foote, who ran the southeast region for the NRCC.

“We had them on the phone numerous times, and there was no mention of fraud,” Gorman said. “It’s unfortunate that there’s a revisionist history going on.”

Foote did not respond to multiple requests for comment. He has been named Harris’ incoming chief of staff, although whether Harris will be seated in Congress in January remains uncertain.

Pittenger said he did not recall being told of fraud complaints his advisers made to Woodhouse and Foote, and he declined to confirm that he blamed “ballot stuffers” on election night.

But he said there was “a lot of angst” among his campaign aides, who “were all upset about what happened.”

“I think there were a lot of frustrated feelings inside the room as we saw the results come in,” he said.

SUBPOENAS, MULTIPLE PROBES

The state elections board is investigating irregularities in mail-in balloting in the 9th District general election – many of them in Bladen County, which had the highest share of mail-in votes in the district, state records show.

Investigators have spoken with witnesses who link Dowless to an effort to collect absentee ballots from voters and are examining whether he or his associates filled out ballots or discarded them, according to people familiar with the probe. It is illegal to collect or tamper with someone else’s ballot.

Multiple voters said in interviews that they handed over their ballots – some of which were not fully filled out and were left unsealed – to people who showed up at their doors and offered to collect them. Two Bladen County women said they worked for Dowless and went door to door asking voters to turn over their ballots, WSOC-TV in Charlotte has reported.

This week, the elections board issued subpoenas to the Harris campaign and its general consultant, Red Dome Group, as well as the local sheriff, James A. McVicker, a Republican who won re-election last month and also hired Dowless to run his absentee-ballot program, according to a person familiar with the investigation.

The Wake County district attorney’s office in Raleigh and the State Bureau of Investigation are also conducting probes, Wake County District Attorney Lorrin Freeman told The Post.

If the board concludes that the irregularities tainted those results, it could toss them and call for a new election. The board has announced plans for a hearing by Dec. 21.