A 66-year-old North Carolina woman was sentenced Thursday to two months in federal prison for helping her boyfriend at the time, a noncitizen, vote, even though federal prosecutors conceded she didn’t check a box on his voter registration form indicating he was a citizen.

The woman, Denslo Allen Paige, was the only U.S. citizen charged among a wave of indictments last summer from the office of Robert Higdon, a Trump appointee for the U.S. Attorney for the Eastern District of North Carolina. She is the first among those charged to receive a prison sentence.

Paige, who works at Walmart, told HuffPost in August that she went with her boyfriend to an early voting site shortly before the 2016 election to see if he was eligible to vote because he had been talking a lot about politics. She said she wasn’t sure whether her boyfriend, a legal permanent resident, was eligible to vote, but because she had volunteered as a seasonal poll worker in the past (and was paid a stipend), she figured someone at the polling place would tell him if he was ineligible. When no one stopped him, he voted.

Paige said she never checked a box on the form indicating he was a citizen, but a copy of the form obtained by HuffPost shows the box was checked. At a sentencing hearing Thursday, Sebastian Kielmanovich, an assistant U.S. attorney, said he believed Paige had indeed not indicated her boyfriend was a citizen, according to a transcript obtained by HuffPost. He noted the boyfriend may have even presented a green card to poll workers.

“I believe the statement she made is true that it was left blank, but somebody later checked it. So it’s not just the defendant and Mr. Espinosa; there’s yet a third person who had to have checked ‘Yes’ after the fact; highly concerning, alarming, and the subject of our ongoing review,” Kielmanovich told U.S. District Judge Louise Wood Flanagan.

But even though Kielmanovich believed Paige had not checked the box, he said she “should have known better” because she had spent time as a poll worker. He said Paige and her boyfriend were essentially testing the election system to see what they could get away with.

“They were just trying to get away with it and see what would happen. And it did work because it was registered,” Kielmanovich said.