Madison - Sauk County District Attorney Patricia Barrett will serve as special prosecutor in the investigation of a physical altercation between two state Supreme Court justices.

Justice Ann Walsh Bradley has said Justice David Prosser put her in a "chokehold" during a June argument over a case in her chambers. Others have said Bradley came at Prosser with fists raised and he put up his hands to block her or push her back.

The incident occurred June 13, a day before the deeply divided court issued a 4-3 ruling upholding Republican Gov. Scott Walker's legislation curtailing collective bargaining for public employees. That case started when Dane County District Attorney Ismael Ozanne brought a lawsuit claiming a legislative committee violated the state's open meetings law in March in forwarding the legislation to the state Senate. Ozanne sought to invalidate the law, and implementing it was delayed for months while the case was pending.

The high court ultimately ruled key parts of the meetings law do not apply to lawmakers.

Once news of the altercation between Prosser and Bradley surfaced, the Dane County sheriff's office launched an investigation. The office gave its findings to Ozanne this month but made no recommendations on whether anyone should be charged.

Ozanne, a Democrat, then asked Dane County Circuit Chief Judge William Foust to name a special prosecutor because Ozanne had brought the case the two justices were arguing about when the incident occurred.

Foust announced Monday that he had selected Barrett and she had agreed to take the case.

Barrett said she did not know how long her review of the case would take because she has not yet seen the Sheriff's Department reports. She said she was not concerned about any politics associated with the case.

"The judge asked me to perform a function that is part of my job duties," she said.

Barrett was elected as a Republican but said she has long advocated making district attorneys' positions nonpartisan.

"Politics should play no role in what we do," she said.

Barrett, 62, said she plans on retiring when her term is up in fall 2012.

Last week, the Sheriff's Department also provided its reports to the Wisconsin Judicial Commission, which oversees the state's ethics code for judges and is separately investigating the case. Jim Alexander, director of the commission, said there was no timeline for conducting its investigation.

If the commission found any wrongdoing, it would have to submit its findings to the Supreme Court to consider. Four of the other five justices were nearby when the incident occurred in Bradley's suite of offices in the Capitol, and the four all apparently saw or heard what happened.