One of the stars of the reality TV series 'Buckwild,' 21-year-old Shain Gandee, was found dead on Apr. 1. At the time, his cause of death was unknown, but now it's suspected that the MTV regular, his uncle and a friend all died of carbon monoxide poisoning.

And while his family is working through their grief, they're trying to come up with the cash for a funeral.

According to sources who spoke to TMZ, the 1984 Bronco the three men died in was stuck in knee-deep mud that covered the SUV's tail pipe -- a situation that would've fed carbon monoxide into the vehicle.

Police refused to confirm or deny this theory, but based on photos of the mud-encrusted ride, it's a highly likely scenario.

Meanwhile, Gandee's family is trying to raise money for the funeral. Ashley Gandee, Shain's cousin, is organizing a memorial mud run as a fundraiser, saying, "I know the strain they are going through. It's hard to provide a proper burial. It's already tough with the loss of family members ... expenses are tough as well."

The mud run is set to take place on Wednesday (Apr. 3) in Proctorville, Ohio, which is about 50 miles away from where 'Buckwild' is filmed in Charleston, West Virginia. The cost for entry is $10 per vehicle. Ashley's shop, Gandee's General Store, is also accepting donations.

Shooting of the second season of 'Buckwild' has understandably been suspended in light of Shain's death.