One woman who helped collect ballots, Ginger Eason, told a local news station that she was paid to collect the ballots and didn’t actually return those ballots to the state. Instead, she said she gave them to L. McCrae Dowless Jr., a Harris campaign contractor.

The state’s extensive voter data, which is among the best in the country, is consistent with the pattern of conduct described.

Bladen and Robeson Counties had unusually high numbers of absentee ballot requests. They also had unusually high numbers of voters who didn’t return their absentee ballots. Put it together, and the two counties stand out for anomalously high numbers of voters who requested ballots and never voted.

The results themselves are also consistent with the possibility that the anomalies in absentee ballots had an effect on the outcome of the election. That’s because throughout the Ninth District, Mr. McCready did an average of 30 points better in the mailed absentee votes than in votes cast in person. Bladen is the only county where Mr. McCready did worse in the mail absentee vote, and Robeson was the county where Mr. McCready had the smallest overperformance, at just six points. The political and demographic characteristics of the returned absentee vote in Robeson and Bladen Counties don’t look unusually Republican.

But it’s hard to assess the magnitude of the effect on the result.

For illustrative purposes, one could assume that voters should have returned ballots at the same rate as everywhere else (which would add several hundred absentee votes to the total), and assume that the overall absentee vote would have been 30 points more Democratic than the non-absentee vote, as was the case in the rest of the district. This back-of-the-envelope estimate would yield a net of 700 votes for Mr. McCready, erasing most of Mr. Harris’s 905-vote lead.