Updated

California's political watchdog agency has announced the largest fine in its history for campaign-reporting violations and ordered two political action committees involved in the 2012 elections to pay the state's general fund $15 million.

The California Fair Political Practices Commission on Thursday called the two Phoenix-based groups that will pay the $1 million fine "part of the `Koch Brothers Network' of dark money political nonprofit corporations." The reference is to billionaire brothers Charles and David H. Koch, who have given millions of dollars to conservative causes across the country.

The investigation and settlement between the state and nonprofits, to be filed in Sacramento County Superior Court, stem from an $11 million contribution last fall to a California group that was fighting a tax initiative and supporting an anti-union one.