California Governor Jerry Brown has accused Proposition 8 supporters of conducting a “witch hunt” against U.S. District Judge Vaughn Walker, who last year struck down the gay marriage ban as unconstitutional, the AP reported.

Walker's ruling came after he presided over a 13-day trail in San Francisco.

Last month – three months into his retirement from the bench – Walker acknowledged that he's gay and in a ten-year relationship with a physician, confirming for the first time a San Francisco Chronicle report published in February.

Lawyers for Protect Marriage, the coalition of socially conservative groups defending the law, have asked for Walker's ruling to be vacated because he's in a long-term relationship with a man.

“If at any time while this case was pending before him, Chief Judge Walker and his partner determined that they desired, or might desire, to marry, Chief Judge Walker plainly had an interest that could be substantially affected by the outcome of the proceeding,” lawyers wrote in a brief filed last month.

Lawyers for Brown accused Prop 8 supporters of engaging in a thinly veiled “witch hunt” in papers filed on Thursday in U.S. District Court in San Francisco, and denied Walker had any reason to recuse himself from the case.