Suppose you thought you had cancer. Suppose you had a son who was in dire straights for money. Suppose you had an insurance policy that was worth quite a bit of money. Would you kill yourself for the insurance money and try to make it look like murder? Why not just wait for the cancer to kill you? Well, maybe you don't want a long gruesome death. Maybe your son needs the money sooner rather than later.
How would you kill yourself so that it wouldn't look like suicide? Maybe a car accident on a mountainous road on a rainy night? No? How about stripping down to your socks, walking into a cemetery, binding your ankles and wrists (the later kind of loosely), writing "FED" on your chest (to make the whole thing look like some redneck hate crime), and then hanging yourself from a tree?
Federal Census worker, Bill Sparkman, should have picked a higher branch to hang himself from. Investigators had several clues that Sparkman's death wasn't a murder. The biggest one was that his knees barely cleared the ground below the branch he was hanging from. If he wanted to live, he just needed to stand up.
Instead of life insurance, maybe Sparkman should have purchased stupidity insurance. (BTW, the autopsy showed that he did not have cancer.)