Madison - Two agencies are investigating a claim by Supreme Court Justice Ann Walsh Bradley that Justice David Prosser put her in a chokehold earlier this month - an allegation Gov. Scott Walker on Monday called extremely serious.

Asked if the reports about Prosser's behavior, if true, merited his resignation, Walker said: "I don't even want to go down that path . . . other than to say that just based on the allegations that were made, I can't overemphasize how serious I think the situation is there. Until we know what happened, I don't think it's best for anybody for me to comment on what the next step is."

The separate investigations are being run by the Dane County Sheriff's Office and the Wisconsin Judicial Commission, which oversees the state's judicial ethics code. The sheriff's investigation was launched Monday; the commission's was authorized Friday and publicly acknowledged Monday.

"After consulting with members of the Wisconsin Supreme Court, I have turned over the investigation into an alleged incident in the court's offices on June 13, 2011, to Dane County Sheriff Dave Mahoney," Capitol Police Chief Charles Tubbs said in a statement.

The sheriff's office in a statement acknowledged it was taking over the case, but declined further comment.

It was not clear why Tubbs would consult with members of the court on who should investigate the matter.

"The sheriff and Judicial Commission can expect the full cooperation of Justice Prosser, who believes a thorough and impartial review will be the proper channel for the facts surrounding this incident to be reported to the general public," Prosser spokesman Brian Nemoir said in a statement.

Prosser himself declined to comment. Chief Justice Shirley Abrahamson, reached by telephone Monday night, was asked about the incident.

"It's under investigation," she said, declining to comment further. Other justices either declined to comment or did not return calls Monday. The justices spent much of Monday working together behind closed doors on cases as they finalize decisions before the end of the court's term Thursday.

After reports were published Saturday about the incident, Bradley told the Journal Sentinel that Prosser "put his hands around my neck in anger in a chokehold." Before Bradley gave her account, Prosser issued a statement saying that reports quoting anonymous sources would be proven false.

Walker told Journal Sentinel reporters, editors and members of the newspaper's Editorial Board on Monday that the current court was the most dysfunctional in his memory, and that the judiciary is supposed to be the most dispassionate of the three branches of government.

"I think, again, beyond the particulars of this case . . . the fact that there appears to be an ongoing friction among justices in the court is something that has to be resolved," Walker said. "I don't know what the right answer is."

Walker raised the possibility of providing a mediator, but was cautious about any involvement from either the executive or legislative branches of government.

Walker also said "long-term, it's worth looking at" an appointed Supreme Court, instead of an elected one, in Wisconsin.

Such a change would require a change in the state constitution.

If Prosser resigned, Walker would appoint his successor.

Different accounts

The court for years has been split by ideological and personal differences.

"Perhaps the most troubling aspect of this stunning development is how, given all that we have learned about the court in recent years, how untroubling many (people) are likely to find this," said Marquette Law School professor Peter Rofes. "Entirely apart from the obvious violent nature of this act - and the fear it engendered in a female member of the court - as each day passes the people of Wisconsin have less reason to believe that there is very much legitimacy left in this incredibly important institution."

The confrontation happened after hours June 13 as the justices argued in Bradley's chambers over a case challenging how the Legislature passed a controversial plan to sharply limit collective bargaining for public employees. The next day, the decision was released by the court, which ruled 4-3 that the measure was passed properly and should go into place.

Sources familiar with the incident have given differing accounts. Some backed Bradley's description, while others have said Bradley came toward Prosser with her fists up and he put his hands out to block her or push her back.

Prosser, 68, and Bradley, 60, are both of slight stature. Prosser's temper is widely known in the Capitol, and last year he blew up at Abrahamson, calling her a "bitch" and saying he would "destroy" her.

Prosser defended himself at the time by saying Abrahamson and Bradley "are masters at deliberately goading people into perhaps incautious statements."

All justices but N. Patrick Crooks were in Bradley's suite of offices when the incident happened. Only Bradley has spoken publicly about it.

Threatening or assaulting a judge is a felony, and those found guilty of it are subject to penalties of up to $10,000 and six years in prison. Simple battery is a misdemeanor with a maximum punishment of a $10,000 fine and nine months in jail. But it is not clear if either of those statutes would be invoked in this instance.

The state Department of Justice and the Madison Police Department are not involved in the criminal investigation, spokesmen for those agencies said.

Dane County District Attorney Ismael Ozanne said he has not talked to law enforcement about the incident but would review anything that is referred to him.

The Democratic district attorney was involved in the case that Bradley and Prosser were arguing about just before the altercation. Ozanne said Monday that if law enforcement recommends charges, he will review whether he has a conflict of interest. When there are conflicts, he refers cases to special prosecutors, he said.

Secret investigations

The Judicial Commission investigation is the third one against a sitting justice in the last five years. Before that, no justice had been investigated by the commission.

The latest investigation could encounter difficulties because matters of judicial ethics are decided solely by the Supreme Court. In this case, two justices were involved in the matter, and four of the five others were witnesses.

The commission conducts investigations in secret. If it concludes a judge has violated the judicial ethics code, it issues a formal complaint. The matter is then heard by a special panel of three appeals court judges.

The judicial panel then makes a recommendation to the Supreme Court on whether it believes the judge violated the ethics code and, if so, what punishment should be imposed. The Supreme Court would then render its ruling; it has the power to reprimand judges, censure them, suspend them without pay or remove them from office.

The Supreme Court in 2008 reprimanded Justice Annette Ziegler for handling cases as a circuit court judge involving West Bend Savings Bank, where her husband was a director. Last year, the commission abandoned a case against Justice Michael Gableman after the court split, 3-3, over whether he violated the ethics code with a misleading campaign ad.

On June 15 - two days after the incident and a day after the court's decision was released - Tubbs, the Capitol police chief, met with all seven justices about the incident involving Prosser and Bradley, sources said. It was not clear Monday whether it was an informal setting; one source said Tubbs never separately interviewed at least three of the justices.

Nationally known police practices expert Melvin L. Tucker said he couldn't figure out why the Capitol police would confer with the justices about the direction of the investigation rather than simply presenting a case to the district attorney.

"There may be justifiable reasons for it, but it doesn't sound like it's normal," said Tucker, a former FBI agent who has served as a police chief in three states and is now based in North Carolina.

"If there was probable cause that a choking actually did take place, if the victim did give a statement to that effect, you go to the prosecutor's office and proceed from there," he said.

Cary Spivak and Gina Barton of the Journal Sentinel staff contributed to this report.