
When it comes to my preference in impossible crimes, the more simple the explanation of the mystery the better and so I found "The Impossible Murder of Dr. Satanus" with its straightforward solution to be a satisfying impossible crime story.
According to the bio in EQMM, Krohn was a university freshman when this story was published and the first detective story he read was (surprise!) John Dickson Carr's The Three Coffins. Although he started his writing career young, it doesn't appear that he published much (if anything else) in the genre. Too bad because this was a promising debut.
I thought this might be an obscure short story to get a hold of, but it was deservingly reprinted in 2007 in The Mammoth Book of Perfect Crimes and Impossible Mysteries.