Officials in Lancaster county, Pennsylvania, are investigating about 2,500 voter registrations after election workers discovered signs that they may be fraudulent.

The registrations under investigation were dropped off in two batches just before Pennsylvania’s voter-registration deadline on Monday. Election workers contacted the district attorney’s office after they noticed several suspicious applications that contained the same handwriting, signatures for voters that didn’t match what was on file, and inaccurate personal identifier information, including names, addresses, social security and driver’s license numbers, said Heather Adams, the district attorney, during a press conference on Friday.

Investigators also spoke with voters who said they had not requested or filled out the forms that were turned in, she said.

The announcement comes as voting is already under way in Pennsylvania, a must-win battleground state for both Donald Trump and Kamala Harris this election. Lancaster county, known for its Amish population, voted for Trump by nearly 16 points in 2020.

Adams did not say how many applications her office had reviewed so far, but said that 60% of them had been fraudulent. She acknowledged that there were some legitimate applications in the batch and said those registrations would be processed.

The effort appears to be associated with a large-scale canvassing group – she did not identify which one – and said that two other counties in the state are investigating a similar issue. The canvassers were paid, a common practice. Officials did not say whether there was a partisan breakdown in the applications.

“It really shouldn’t matter. If there’s voters on the books that shouldn’t be, it increases the chance that we’re gonna have voter fraud,” Williams said.

The announcement comes days after the county was accused of wrongfully holding up voter-registration applications from students.