ELIZABETHTOWN, N.C. — Democrats have been quick to argue that their losing candidate for Congress in North Carolina’s Ninth District may have been a victim of election fraud. But there might be a Republican victim as well.

He is outgoing Representative Robert M. Pittenger, whose narrow loss to Mark Harris in the Republican primary in May is just about as studded with red flags suggesting absentee ballot fraud as the general election now under scrutiny.

As with the November general election, most of the concerns about the primary center on Mr. Harris’s extraordinary success with absentee voters in Bladen County, a rural swath of southeastern North Carolina where L. McCrae Dowless Jr., a shadowy contractor with a history of suspect voter turnout efforts, worked for Mr. Harris’s campaign.

In that primary against Mr. Pittenger, Mr. Harris won 437 of the 456 ballots cast through the mail in Bladen County; his overall margin of victory was only 828 votes. By contrast, in an earlier run against Mr. Pittinger in 2016, Mr. Harris won only four of 226 such ballots in the county. Mr. Dowless did not work for Mr. Harris in that campaign.