BATON ROUGE, La. (AP) — A judge has voided the result of a Louisiana sheriff’s election that was decided by a single vote and ordered a new runoff be held, saying there is evidence a handful of ballots were cast illegally.

Ruling this week, specially appointed Judge E. Joseph Bleich ordered a new election for sheriff in Caddo Parish, one of Louisiana’s most populous parishes, in the northwest corner of the state.

Democrat Henry Whitehorn had been declared the winner last month after topping Republican John Nickelson by the slimmest of margins, from more than 43,000 ballots cast. A recount produced the same result — a one-vote edge for Whitehorn.

Bleich said in his ruling that it was “proven beyond any doubt” that there were at least 11 “illegal votes cast” — making it “legally impossible to know what the true vote should have been.”

“Just one illegal vote could have affected the outcome, and here, multiple illegal votes were cast and counted,” Bleich wrote.

Bleich said at least five absentee mail-in ballots were missing a required witness signature and should not have been counted.

In addition, two people voted twice and four votes were cast by unqualified people, such as individuals incarcerated for a felony conviction, Mike Spence, the Caddo Parish clerk of court, confirmed to The Associated Press following the recount.

“Human mistakes were made on election day,” he said.

The secretary of state’s office declined to comment on the ruling or about improper ballots, saying it cannot discuss issues currently being litigated.

Whitehorn has said he will appeal the ruling.

“The significance of a single vote cannot be underestimated,” he said in a statement. “Overturning an election because the winner won by one vote is essentially saying, ‘Every vote matters, except if the win is by one.’”

Nickelson, who challenged the election result, said via social media that he was grateful for the ruling, which he called “a victory for election integrity.”

It is the country’s second local election this year in which a judge has voided the result, after a judge last month ordered a redo of a Democratic mayoral primary in Connecticut’s largest city due to possible ballot stuffing, a case that fueled conspiracy theories pushed on social media.

The topic of election integrity has also been at the forefront of national politics after former President Donald Trump’s false claims about the 2020 presidential election.

The one-vote margin in the Caddo Parish sheriff’s race also put a spotlight on Louisiana’s recount process. It is the only state that continues to use paperless touchscreen voting machines, which do not produce an auditable paper trail that experts say is critical to ensure results are accurate.

Louisiana’s mail-in absentee ballots currently constitute the state’s lone auditable paper trail that can be tallied again and checked for errors. Absentee ballots accounted for about 17% of the vote in the Caddo Parish race.

Election officials including Louisiana Secretary of State Kyle Ardoin have reiterated that the state’s elections are secure and there are checks and balances to ensure voting integrity.

Louisiana has been trying to replace the paperless machines for the past five years, but that was delayed after allegations of a rigged bidding process.

States’ recount abilities proved highly important during the 2020 presidential election, when multiple battleground states conducted recounts and reviews that confirmed President Joe Biden’s victory.