Frank Hudson was a private investigator and one-time employee of Special Agent Pendergast. Short and stocky, Hudson was a former police officer, until diabetes forced him off the street. Unable to handle working behind a desk, he quit the force and went into business as a private investigator. His main client was art dealer and illegal wildlife smuggler John W. Blast, for whom Hudson would perform background checks of potential business partners and suppliers. He drove a vintage Ford Falcon.