updated 04/02/2013 AT 1:45 PM ET
•originally published 04/02/2013 AT 3:45 PM ET
As friends and fans mourn the loss of Shain Gandee, authorities say the Buckwild star and two others died due to toxic exhaust fumes filling their stuck-in-the-mud SUV.
The 21-year-old reality TV personality, his uncle and another man who has not officially been identified were found unresponsive in Gandee’s Bronco on Monday morning, after being reported missing since early Saturday morning.
“Foul play has been ruled out,” Kanawha County Commissioner Kent Carper of West Virginia told PEOPLE on Tuesday.
Autopsies later confirmed the men died of the gas and that the deaths were accidental.
With the vehicle knee-deep in mud, toxic fumes from the car were likely unable to escape through the tailpipe, authorities say.
Gandee’s cousin, Ashley Gandee Lewis, says on Facebook: “The family feels that Shain died peacefully in his sleep without pain or suffering.”