Federal authorities have identified an additional group of more than 17,000 potential noncitizen voters as part of their ongoing challenge to California’s voter rolls, a development disclosed in court documents filed this week. The move comes amid heightened scrutiny of voter registration accuracy ahead of the state’s November 3 election.

The federal investigation centers on a previous list compiled by U.S. Citizenship and Immigration Services (USCIS) that included approximately 20,000 individuals flagged as “likely noncitizen” voters. Nicolas Bartell, associate director of USCIS’s Fraud Detection and National Security Directorate, revealed in a sworn affidavit on Monday that his agency had also created a “separate batch” of more than 17,000 voter records potentially linked to noncitizens. He added that USCIS continues to receive and review records on a rolling basis prior to the election.

However, officials in Los Angeles County have challenged the reliability of the government’s initial data. Monica Flores, a senior official with the Los Angeles County Registrar-Recorder/County Clerk’s office, stated in a separate affidavit that a preliminary examination of a random sample of 200 registrations from the earlier 20,000-person list found that nearly 40 percent of those individuals were born in the United States. The county suggested this discrepancy calls into question the accuracy of the federal government’s voter fraud claims.

The dispute highlights ongoing tensions between federal authorities and local election officials in California concerning the integrity of voter rolls. The federal inquiry is described by USCIS as an unprecedented attempt to identify potential noncitizen voters in one of the nation’s largest states.

California’s county election officials have maintained that their registration processes are robust and that the state has safeguards in place to prevent noncitizens from voting illegally. Meanwhile, the federal government argues that verifying and cleaning voter rolls is essential to ensuring fair and lawful elections.

As the investigation continues, both sides appear set to present competing data on the scope and nature of alleged noncitizen voter registrations. With just weeks remaining before Election Day, the controversy adds to the broader national debate over voter fraud and election security.