A county prosecutor is accusing Arizona Attorney General Tom Horne of campaign finance violations during his 2010 campaign.
Maricopa County Attorney Bill Montgomery says the allegations in a planned civil enforcement action stem from an FBI investigation into $500,000 of spending by a group that was led by a Horne ally.
He says there were violations of state law prohibiting coordination between campaigns with groups that are supposed to be acting independently to support or oppose candidates.
Montgomery says there could be a civil penalty of up to $1.5 million.
But he says no individual would be held personally responsible and that there's no penalty if the groups agree to refund larger-than-allowed contributions.
Horne didn't immediately respond to a request for comment.
He has said previously there was no coordination.