In the 1990s I wrote a book about the gangsters Roger Touhy who was murdered by the mob in December of 1959. This information was sent to me by a highly placed source in law enforcement who worked on the Mob detail in the 1950s-1960.
You probably are aware of the following: The two mopes that shot Touhy & Miller on December 16, 1959 when they arrived home after attending a meeting were Phil "Milwaukee" Phil Alderisio and Albert "Obie" Frabotta.
My source is highly trustworthy and very reliable who I have known for many years. The reason given for killing Touhy was he was a potential threat to their operations.