UPDATE: 12:55 p.m. May 17, 2012 -- Preliminary autopsy findings from the Ascension Parish coroner indicate that "Swamp People" star Mitchell Guist died of natural causes. Guist would have turned 48 Friday. Funeral services will be held Saturday in Gonzales at Ourso Funeral Home.

UPDATE: 2:22 p.m. May 14, 2012 -- Assumption Parish Sheriff Mike Waguespack says Mitchell Guist, a popular star on the History Channel reality show 'Swamp People,' was evidently loading something onto a boat on the Belle River Monday morning when he slipped and fell.

Witnesses say they saw Guist fall backwards into the boat. They immediately took the boat to the dock and called 911.

Waguespack says Guist may have had a seizure, but the official cause of death has not yet been determined.

1:33 p.m. -- Mitchell Guist, a popular star on the History Channel reality show Swamp People, has died.

Major Ginny Higgins with the St. Martin Parish Sheriff's Office tells us they received a medical call Monday at 9 a.m. to a boat on the Belle River.

Acadiana Ambulance transported Guist to Teche Regional Medical Center where he was pronounced dead.

It's still unclear how Guist died. We will continue to bring you updates on this breaking story as it develops.

The Guist brothers did an interview with our sister station 97.3 The Dawg last year during the Louisiana Outdoor Expo.