The camper had high levels of carbon monoxide.

Authorities in northwestern North Dakota say a couple from Las Vegas, Nevada, have been found dead in a camper with high levels of carbon monoxide.
Authorities were called Tuesday about a man and a woman found non-responsive in the camper parked in Williston, according to the Williams County Sheriff's Office. Carbon monoxide levels in the camper were at 400 parts per million, well above safe levels, authorities said.
The sheriff's office identified the married couple as Jesse Parker, 45, and Michelle Parker, 46. Authorities said the deaths are not suspicious and there will be no further investigation.