A county clerk likely violated the law when she failed to report thousands of votes in this spring's tightly contested Wisconsin Supreme Court election, but her conduct wasn't criminal, state investigators said Wednesday.

Waukesha County Clerk Kathy Nickolaus touched off a firestorm in April when she revealed she hadn't reported 14,000 votes in the race between conservative Justice David Prosser and challenger JoAnne Kloppenburg.

The contest evolved from a sleepy race between an incumbent justice and a little-known state attorney to a heated referendum on Republican Gov. Scott Walker's collective bargaining law, which stripped almost all public workers of most of their union rights. The measure's opponents made Kloppenburg their champion, hoping she would replace Prosser and help strike the law down.

Nicholaus couldn't explain how she failed to report the votes, investigators said, but they concluded she probably loaded a blank template into a reporting database rather than a template that contained the vote totals. Wisconsin law requires county clerks to post all returns on Election Night.

Former Dane County prosecutor Timothy Verhoff, who led the probe, said Nickolaus' flub wasn't intentional and she wasn't trying to conceal votes.

The state Government Accountability Board, which oversees Wisconsin elections, won't refer the case to Waukesha County prosecutors, board spokesman Reid Magney said. However, the board ordered Nickolaus on Wednesday to release detailed results on Election Night rather than county-wide figures, a process that would make errors more visible. The board also told her to develop written procedures for reporting results.

Nickolaus issued a statement Wednesday saying she was glad the investigation confirmed she made an honest mistake. She promised to follow what she termed the board's "recommendations" and said she looked forward to "rebuilding the trust of Waukesha County residents in the election process as it is the foundation of our democracy."

Initial results from the April 5 election showed Kloppenburg upset Prosser by about 200 votes. But two days later, Nickolaus held a news conference to announce that she failed to report votes from the city of Brookfield, which flipped the race for Prosser. A statewide recount confirmed his victory.

Questions swirled about whether Nickolaus, who worked for Prosser when he was a Republican legislator, was trying to stack the election for her former boss.

The board launched a review, but Kloppenburg's campaign demanded an independent investigation. The board hired Verhoff, now a criminal defense attorney, to run the probe.

According to his report, Nickolaus told investigators she sent blank templates to her municipal clerks, who were supposed to enter vote totals and send them back to her to upload into the county's database. Brookfield's clerk sent her spreadsheet back with the results, but Nickolaus apparently uploaded a blank template in place of Brookfield's numbers.

If a second person had verified the results or if Nickolaus posted results by ward rather than countywide totals, the mistake could have been spotted, the report said.

The report went on to say a general lack of communication and transparency after Nickolaus discovered the mistake made matters worse.

Nickolaus shared information about the problem with a very limited number of people and failed to convey any urgency to the Government Accountability Board the day after the election, the report said. Her decision to hold a news conference before she knew exactly what she had done wrong added to the conspiracy theories, the report added.

The board released the findings from its review on Wednesday as well. It largely mirrored Verhoff's conclusions.

Kloppenburg's campaign manager, Melissa Mulliken, said the investigations vindicated their suspicions that Nickolaus broke the law