The cause and manner of death of a Jefferson man has been determined.

The Polk County Medical Examiner’s office performed an autopsy and determined the manner of death for 60-year-old Ronald Kolbeck was natural. The cause of death was from hypertensive and atherosclerotic cardiovascular disease. 

Kolbeck was involved in a one-vehicle crash that happened at 11:57pm Saturday, June 22nd. The Iowa State Patrol reports Kolbeck was heading east on County Road E-53, when his 2012 Ford F-250 truck struck a bridge rail. Kolbeck was transported to the Greene County Medical Center by Greene County Ambulance. He was later taken to Iowa Methodist Medical Center in Des Moines, where he died from his injuries. 

We’ve previously reported that the State Patrol confirmed alcohol did play a factor in the incident, and that Kolbeck’s blood alcohol level was above the legal limit of 0.08. Greene County Sheriff Jack Williams said Kolbeck was seen by a Greene County Deputy the night of June 22nd during an event at River Farms Recreation prior to the accident. River Farms Owner Craig Flack previously told Raccoon Valley Radio Kolbeck was with him the majority of the time that day and he didn’t witness him consuming alcohol.