A judge ruled Monday that Arizona’s Republican attorney general did not violate campaign finance rules.

Tom Horne was accused of illegally coordinating with aide Kathleen Winn during his 20-10 election campaign, when Winn was running an independent expenditure committee. Yavapai County prosecutors want Horne to repay $400,000 to donors and pay as much as three times that in civil fines. They accused Horne and Winn of working together on an ad campaign attacking Horne’s 20-10 opponent, Democrat Felecia Rotellini. She is once again running against Horne this year.

The administrative law judge who heard the case wrote in her ruling that the evidence presented by prosecutors was circumstantial. Yavapai County Attorney Sheila Polk has 30 days to decide how to act on the ruling. If she rejects it and pursues the fines, Horne and Winn could take the case to court.