Authorities are investigating a case of potential voter fraud in Tuesday’s gambling referendum in Linn County. According information provided by Iowa Secretary of State Matt Schultz, an unidentified woman walked into a polling place, claiming to be a registered voter.

The woman signed the election register and cast a ballot. Later Tuesday, the “actual registered voter” tried to vote, but discovered someone else had voted in her name. The real voter cast a provisional ballot.

The impersonator’s ballot was included in the final tally. The precinct board will have to decide whether to count that provisional ballot, too. Iowa Secretary of State Matt Schultz says future cases like this could be stopped with a “common sense voter I.D. law in Iowa.”

Tuesday’s gambling referendum in Linn County passed with 61 percent of the vote.