A prosecutor asked the Wisconsin Supreme Court on Friday to reopen his lawsuit challenging Gov. Scott Walker’s contentious collective bargaining law, contending a justice who voted to dismiss the suit earlier this year got free legal help from the firm defending the law.

Dane County District Attorney Ismael Ozanne argued in filings with the court that it should vacate its decision because Justice Michael Gableman never disclosed his arrangement with the Michael Best and Friedrich law firm. Wisconsin’s ethics code prohibits state officials from accepting free gifts, and the judicial ethics code bars judges from accepting gifts from anyone likely to appear before them.

Ozanne asked the court to reinstate a circuit judge’s earlier ruling declaring the law void and disqualify Gableman from participating in further proceedings if he won’t recuse himself.