"Swamp People" star Mitchell Guist was building a houseboat when he appeared to suffer a seizure and fell backwards on the watercraft, Louisiana officials said.

Assumption Parish Sheriff Mike Waguespack described to CNN the circumstances of the alligator hunter's death Monday on the Intercoastal Waterway.

Daniel Wiltz of the St. Martin Parish coroner's office said he expects autopsy results to be announced Wednesday.

Guist, 47, was pronounced dead at Teche Regional Medical Center in Morgan City.

"Right now, we're thinking about him almost every minute," Brian Catalina, executive producer of The History Channel's "Swamp People," told CNN. "We've lost a really important part of our family and a treasured friend."

Guist starred on the show alongside his brother, Glenn.

"The two were inseparable. These guys were born in the same house that they both still lived in, up until yesterday. They were two peas in a pod for sure. Neither had ever married. They were just as brothers as you could be," Catalina said.