GUTHRIE COUNTY, Iowa -- Federal investigators are releasing their preliminary findings on a plane crash that killed four people in Guthrie County last month.
Investigators say those onboard died of carbon monoxide poisoning when a two-inch crack in the muffler allowed gas into the cockpit. Investigators found soot on the inside of the muffler and inside the cabin heat hose.
The four killed were 49-year-old Edward Anderson, 36-year-old Pat Kellen and 15-year-old Samantha Clark, all of Le Mars, and 28-year-old Tyler Douvia of Merrill.
They were on their way from Le Mars to Osceola for a hunting trip.