Election officials in one Ohio county found that about 2,600 ballots were double-counted, and two other counties have discovered possible cases of people voting twice in the presidential election (search).

Prosecutors were trying to determine Wednesday whether charges should be filed against a couple in Madison County (search) accused of voting twice. In addition, Summit County election workers investigated possible double votes found under 18 names.

In the other case, Sandusky County (search) election officials discovered that about 2,600 ballots from nine precincts were counted twice, likely because of worker error, elections director Barb Tuckerman said.

Tuckerman believes the votes were counted twice when they were mistakenly placed alongside a pile of uncounted ballots. The room where the ballots were being fed into optical-scan machines on election night was so crowded that ballots had to be placed on the floor, Tuckerman said.

"It was totally hectic," she said.

The problem was discovered when Tuckerman found that one precinct showed 131 percent of registered voters had cast ballots.

President Bush won the election by taking Ohio with 136,000 votes more than Democrat John Kerry, according to the unofficial tally.

The couple who voted twice in Madison County cast absentee ballots in October, then voted in person on Election Day, county elections director Gloria Herrel said. The couple said election workers told them their absentee votes were lost, prosecutor Steve Pronai said.

In Summit county, typically the votes were made by absentee ballot or in person, and then a second vote was cast with a provisional ballot in another precinct, elections director Bryan Williams said.

Under Ohio law, people who vote twice could be charged with election fraud, falsification or illegal voting, according the Secretary of State's Office. The maximum penalty for the most severe charge is 18 months in prison.

Double votes could have affected the result of a local schools income tax request that failed by one vote in Madison County.

In Illinois, thousands of provisional ballots cast on Election Day did not count, in most cases for lack of evidence the voters were actually registered. The Associated Press count was based on checks of several election jurisdictions. State officials were still gathering information Wednesday on provisional ballots cast statewide, a day after the deadline to count them.