The Iowa Secretary of State's office said Thursday it is willing to work to fix a problem that led to three northern Iowa voters having their ballots tossed out of the 2012 election.

Meanwhile, officials in several county auditors' offices said that although they think the problem experienced by the three is rare — or at least that it hadn't happened in their jurisdictions — they recognize the statewide voter database that improperly included their names has errors.

"The important thing is now that we know there was this flaw that exists, we're going to work with the Secretary of State's office to fix it," said Eric Van Lancker, the Clinton County auditor who is president of the state auditor association.

About 46,000 people are on the database of felons who are prohibited from voting.

The database is compiled from lists of convicted felons that, by law, are to be sent monthly by the 99 county clerks to the secretary of state's office, as well as to their local county auditors' offices.

In the case in Cerro Gordo County, three eligible voters were improperly included on the database, according to Ken Kline, the county auditor.

He said they had their ballots challenged during the 2012 election, and after his office confirmed with the secretary of state's office that they were on the felon database, they did not count them.

Only later did a Division of Criminal Investigation agent, working for the secretary of state, discover they should not have been excluded, Kline said.

One had been charged with a felony but not convicted, Kline said. A second had a felony conviction resolved because of former Iowa Gov. Tom Vilsack's 2005 executive order restoring voting rights to felons discharged from prison, parole or supervision. A third had his rights restored because of Vilsack's order and because a felony charge was reduced to a misdemeanor.

After he was elected in 2010, Iowa Gov. Terry Branstad rescinded the order.

Senate Democrats have scheduled a hearing for Monday on the Cerro Gordo voters, and Secretary of State Matt Schultz is scheduled to attend.

Chance McElhaney, a spokesman for the secretary of state's office, said the responsibility for the accuracy of the database rests with the clerks of court, not the secretary of state's office. Still, he said Thursday the office will follow up on the matter.

"We'll be working with the Legislature, the governor's office, judicial branch and county auditors to figure out how best to resolve the issue," he said.

Sen. Jeff Danielson, D-Cedar Falls, who chairs the Senate's State Government Committee, rejected the idea the problem is the fault of the clerks.

"If the secretary of state wants to be the state election official, he owes it to Iowans to do his due diligence, to verify the accuracy of information he's using to make those decisions," he said.

Officials in several county auditors' offices said Thursday they realize the database can contain errors.

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Roland Caldwell, the operations manager for the Scott County Auditor's office, said they have found instances in which an individual was charged with a felony but, after checking with the court system's online database, they find the charge was reduced. Still, they were on the list of prohibited voters.

"I wouldn't say very often, but it does happen," he said.

In addition to reduced charges, some auditors say they have come across cases in which a felon can meet the terms of a court-approved agreement and have the conviction expunged from their record but still be on the list.

The list of prohibited felons isn't the only database that can have flaws. Some auditors say they have found errors in the state-generated list of the deceased that's used cull voters from voting rolls.

Some auditors said they even keep track of obituaries in their local newspapers to help keep their rolls clean.

Other auditors said they think what happened in Cerro Gordo County is rare. Van Lancker said he's never heard of an incident like it.

Still, he and others said that it's important that nobody lose their right to vote.

"Anytime that someone has a chance of having their voting rights taken away erroneously, I think it's an issue," said Carla Becker, the Delaware County auditor.