Prosecutor Elmon Middleton murder in 1935

[Dwalin2014]

Were just browsing through the "Chicago Tribune" archives and found this:
http://archives.chicagotribune.com/1935 ... -in-harlan

So there was a murder of a county prosecutor in Harlan, Kentucky in 1935, blown up with a bomb (so much reminds me of Toto' Riina's style in Sicily). How is it that it seems not to be covered by any book or any list of killed prosecutors or other law enforcement in the USA that may be found on internet? After all, it's not Sicily of the 80s-90s, you don't have a prosecutor clamorously whacked every day, even in the 30s or the so-called "roaring 20s", theoretically whacking a prosecutor should have made more headlines. The only thing I managed to find in some newspaper articles in that the one behind the bombing was some slot machine operator named Otis Noe, and there were other 3 or some more of his gang on trial. This link
https://casetext.com/case/noe-v-commonwealth-3
indicates he was sentenced to life imprisonment, doesn't specify how much the others got.
Still, what kind of gang was that? Any connection to the Cosa Nostra? What was the crime scene in Harlan back then? I checked some books about the city, but they mostly talk about the local mining activity and the political movements connected with it, while the Elmon Middleton murder is only briefly mentioned.