Very sad indeed.
First responders found no fuel leaking from the tanks. Departure was near Denver, CO. to Grandbury, TX. about 600 miles. Winds here were from the east meaning he had a head wind. That is a long legged flight in a loaded RV-6.
Other eyewitness reports say he stalled on final.
I certainly am not trying to speculate, but I know a couple of the eye witnesses / first responders, and they are still petty shook up.
My thoughts and prayers go out to the family for their loss, and for a speedy recovery of the passenger.