INDIANAPOLIS (AP) — A government watchdog group is suing Indiana Secretary of State Connie Lawson, accusing her office of allowing voters to be illegally purged from the state's voting roles.

Common Cause Indiana is asking a federal judge to put a stop what it calls "discriminatory and illegal" practices the Republican secretary of state's office adopted in the wake of new state law that went into effect in July. Lawson's general counsel has dismissed the allegations as "baseless."

At issue is how the election division in Lawson's office allows local officials to remove voters from their rolls if it is believed that they have moved to another state.

Common Cause says the National Voter Registration Act of 1993 allows voters to be removed only if they have confirmed in writing that they have moved, or if they fail to respond to a written notice and do not cast a ballot for at least two general election cycles. But Lawson's office is allowing elections officials to purge registered voters if they show up as recently registered in another state in the Interstate Voter Registration Crosscheck Program.

Lawson's office has argued that if someone moves to a new state and registers to vote, their new registration essentially serves as written notice that they are canceling their registration in Indiana.

But Common Cause, a left-leaning group, notes that the data the state is relying on comes secondhand from a program that has been criticized for its inaccuracy. The Crosscheck database, which roughly 30 states feed information into, is maintained by Kansas Secretary of State Kris Kobach, who has burnished a national reputation for pushing restrictive voting laws and is also the head of President Donald Trump's voter fraud commission.

"Even the Crosscheck Participation Guide admits that 'a significant number of apparent double votes are false positives and not double votes,'" the lawsuit, filed Friday, states. "Several states already have ceased using Crosscheck, with at least one publicly attributing the move to Crosscheck's unreliability."

"Hoosiers are at risk of being disenfranchised unlawfully," the suit says.

The program finds duplicate registrations based on names and birthdates. But data experts are skeptical of Crosscheck, which handled more than 98 million voter records this year with roughly 3 million possible duplicates. A study this year by researchers at Stanford, Harvard and Yale universities noted a high error rate.

Lawson's office declined to comment Sunday. But in a written response to Common Cause, Lawson's general counsel, Jerold A. Bonnet, said Indiana practices are "designed to only identify potential registration matches that are highly likely to be one and the same individual — and to reject any potential match in any instance where the available data is insufficient."

Bonnet also rejected the suggestion that the secretary of state's office is using the process "for partisan effect" or as a "weapon of voter suppression."

This isn't the first time Lawson has drawn scrutiny over her handling of the state's voter rolls. The Indiana NAACP and the League of Women Voters filed a similar lawsuit over the summer.

In the run up to the 2016 presidential election, Lawson raised concern about possible vote fraud by publicly stating that thousands of voter registrations had been altered.

She later walked back the comments, acknowledging that many of the altered registration records might just have been residents rushing to correct their names or birth dates ahead of the election.