CHATTANOOGA, TN. (Times Free Press) -- Scottie Mayfield's congressional campaign says a top aide to U.S. Rep. Chuck Fleischmann illegally provided the brainpower behind a television ad that claims Mayfield is "good at ice cream, not so good on the issues."

The Fleischmann campaign vigorously denied involvement in the ad, which was paid for by a South Carolina group. But Mayfield consultant Tommy Hopper stood by his allegations, implicitly accusing the congressman's chief of staff of violating federal law.

"We simply do not believe that an out-of-state PAC with no known ties to Tennessee has any interest in our primary unless led here by one of our opponents," Hopper said.

Federal regulations prohibit candidates, campaigns and their agents from "coordinating" on independent expenditures made by outside political committees. In general, independent expenditures for or against a candidate are considered "coordinated" if they're made in cooperation or consultation with a campaign.

Read more on the story from our news partners at the Chattanooga Times Free Press.