A 26 year old Palm Bay man has pleaded guilty in federal court following what authorities call the largest seizure in the nation of a newly banned synthetic kratom derivative. Maxwell Horvath admitted to possessing a firearm as a convicted felon after a multi-agency raid uncovered about 92,000 pounds of the substance, along with machine guns, explosives, and ammunition. Federal prosecutors say additional charges tied to explosives and drug manufacturing are still under review. Horvath remains in custody as he awaits sentencing.