Mitchell Guist

"Swamp People" star Mitchell Guist was testing out a new houseboat he was building at the time of his death ... a dream project he had worked on for months ... and now one of his co-stars has vowed to finish the job as a last tribute to the fallen reality star. The man behind the promise is Glenn…

10:19 AM PDT -- Law enforcement sources tell us ... Mitchell was out in his boat along the Belle River ... when he "fell." Witnesses say he appeared to have been suffering from a seizure. We're told another person on the boat returned the vessel to the dock and called 911. Emergency personnel…