INDIANAPOLIS, Oct. 7 (UPI) — Indiana State Police have expanded their investigation into potential voter registration fraud by a nonpartisan group that now encompasses 56 counties.

Investigators raided the office of the Indiana Voter Registration Project in Indianapolis on Tuesday after obtaining a search warrant. In the days since, they said their investigation has expanded from nine counties to 56.

Clerks in several Indiana counties said they had received fraudulent voter registration forms and traced them back to the IVRP. Leaders of the group, which describes itself as nonpartisan, have denied wrongdoing and said they are being targeted by the state in order to suppress voter turnout.

The IVRP hires canvassers across the state to try to get individuals, particularly African-Americans who are not registered to sign up to vote. Investigators said the group has submitted hundreds of registration forms that contain a mix of legitimate and incorrect information, such as a person’s legal name, but an incorrect address or telephone number.

The result could be that those affected face problems voting on Election Day and may have to cast provisional ballots until election monitors sort out the discrepancies.

While the Indiana Voter Registration Project said its mission in nonpartisan it is backed by the liberal-leaning group Patriot Majority. The group’s president, Craig Varoga, said the IVRP is being targeted by the state as a means of suppressing the black vote in November’s election.

“This raid is part of a partisan effort to rig the election by suppressing the rights of tens of thousands of African Americans to vote this November. In conducting their partisan raid, these so-called investigators violated numerous legal standards, including — but not limited to: Denying staff the opportunity to contact an attorney; telling staff that if an attorney were contacted, a state trooper had to be present; and denying the Project’s attorney access to the office and staff,” Varoga said in a letter to the Justice Department requesting an investigation into the motives behind the state police probe.

A statement from the Indiana State Police said the investigation is “complex” and will likely continue after the election. Investigators denied any partisan motivation behind their probe, saying they were acting on complaints from election workers in multiple counties who flagged potentially fraudulent registration forms.