Wisconsin Supreme Court Justice Ann Walsh Bradley officially recused herself yesterday from an ethics probe into fellow Justice David Prosser. The investigation involves a physical altercation between the two in 2011 in which Prosser is alleged to have put his hands around Bradley’s throat. Prosser claims he was defending himself from her in the incident.

In the letter recusing herself, Bradley alleged a history of abusive actions from Prosser. She said the Wisconsin capitol chief of police advised Bradley and Chief Justice Shirley Abrahamson “to take steps for personal security, including locking ourselves inside our personal offices when working alone at nights and on weekends.”

The Milwaukee Journal-Sentinel reports:

Bradley’s departure from the ethics case leaves just two justices on it – Abrahamson and N. Patrick Crooks. Even before Bradley decided to remove herself from the case, it was stalled because four justices are needed to act on cases. It appears unlikely that the case against Prosser can advance further, though some legal observers believe there are ways that it could.

Here’s the backstory on the incident, also courtesy of the Journal-Sentinel:

On June 13, 2011, Prosser, (Justice Patience) Roggensack and two other justices went to Bradley’s office to confront her and Abrahamson in their effort to release a court decision upholding Gov. Scott Walker’s restrictions on collective bargaining for public employees. The four justices wanted Abrahamson to issue a news release saying the decision would come out the next day, but Abrahamson rebuffed them.

Bradley went over to Prosser in an effort to get him to leave her office. Prosser contends she charged at him with her fist raised – a characterization Bradley disputes. Prosser then put his hands around Bradley’s neck in what he says was a defensive gesture.

A special prosecutor found criminal charges were unwarranted. The state Judicial Commission filed ethics charges against Prosser with the Supreme Court in March 2012 saying he violated the ethics code for judges. That case quickly stalled as justices began recusing themselves from it.