CROSSVILLE TENN. — The Tennessee Wildlife Resources Agency says two boaters and their pet died from carbon monoxide poisoning on Chickamauga Lake Monday.  Kristy D. James and Mike L. Richardson of Chattanooga were last heard from Saturday and reported missing early Monday morning. The Hamilton County Sherriff’s Department located the boat floating in a cove near the 477 mile marker, near Harrison Island. The bodies of both victims and their pet were discovered. The case remains under investigation. TWRA confirms three previous fatalities resulting from carbon monoxide poisoning since 2010. Enclosed cabin boats were involved in all of the incidents.