A secret investigation into Republican Wisconsin Gov. Scott Walker's former aides and associates closed last week without any charges being filed against Walker.
Milwaukee County District Attorney John Chisholm announced Friday that the so-called John Doe investigation into illegal campaign activity ended on Feb. 20.
The investigation has hounded Walker - a possible 2016 presidential candidate - throughout his first two years in office. Walker steadfastly and repeatedly denied he had done anything wrong, even as six people around him were charged with crimes stemming from activity in the Milwaukee County executive's office when Walker held that position.
Walker was county executive for eight years prior to being elected governor in 2010.
Walker said he was glad the investigation was over.
"We appreciate the effort that was undertaken and to bring appropriate matters to justice," he said in a statement issued through his campaign.
The investigation began in May 2010, six months before Walker was elected governor.
Walker hired high-profile criminal defense attorneys from Chicago, started a legal defense fund that grew to $200,000 through the end of 2012 and met voluntarily with prosecutors in April. He always maintained his innocence and said he did not know that county workers were illegally campaigning while on the job. Walker said he had built a firewall to ensure county workers were not ordered to do campaign work while on county time.
Democrats insisted that evidence uncovered during the investigation showed that Walker was involved in illegal campaigning.
The people charged in the probe were:
• Kelly Rindfleisch: Walker's deputy chief of staff. She was sentenced to six months in jail after pleading guilty to felony misconduct in office for doing campaign work on county time.
• Tim Russell: Walker's deputy chief of staff, Russell, was sentenced to two years in prison in January after he was convicted of stealing more than $20,000 from a nonprofit group Walker appointed him to lead.
• Darlene Wink: The former Walker aide pleaded guilty to two misdemeanor charges of working on Walker's gubernatorial campaign on county time. She was sentenced to a year's probation.
• Kevin D. Kavanaugh: Walker named Kavanaugh to the county Veterans Service Commission. Kavanaugh was found guilty of stealing more than $51,000 that had been donated to help veterans and their families. He was sentenced to two years in prison.
• William Gardner, president and chief executive officer of Wisconsin & Southern Railroad Co., was sentenced to two years' probation in July after being found guilty of exceeding state campaign donation limits and laundering campaign donations to Walker and other Wisconsin politicians.
• Brian Pierick: The longtime domestic and business partner of Russell was found guilty of contributing to the delinquency of a minor after investigators examined his and Russell's phones and computers. The criminal complaint said Pierick exchanged text messages with a 17-year-old boy and tried to entice him into his van, but the boy declined, according to the criminal complaint.