They said they were involved in working with Morgan County Judge-Executive Tim Conley to ensure their construction company would get the lowest bids in the cleanup and rebuilding efforts.
Conley is accused of getting kickbacks in return.
The Gambills could receive up to 20 years behind bars when they are sentenced on November 18 in Frankfort.
Conley, meanwhile, has pleaded not guilty to his charges.
His trial is set for August 25 in Frankfort.