It is a JFK conspiracy book but I don't know if that part of it is true but an excellent recollection of 20th century New Orleans history & brief Italy history prior to the turn of it, there was a lot of oppression early 1900s - late 1800s & mafia organization was sort of a response to that. Which is why the no talking to authorities part was emphasized.

I'd be interested in more Italy-mob history, that looks like an excellent book I'll have to check out.

On edit -- the links at the bottom of the story are excellent for the sort of the thing I was looking for

Italian police solve century-old Mafia murder mystery

A probe into modern day Cosa Nostra crime in Sicily stumbled upon evidence which appears to have solved a 100-year-old Mafia murder mystery.

Police arrested 95 people on Monday (June 23) for extortion, drug trafficking and money laundering.

But, in the process, Italian officers may also have solved the century-old mob murder of a New York detective.

Joe Petrosino, a New York police detective, was shot dead while on the island to collect evidence for a Mafia probe in 1909.

Domenico Palazzotto, among the 95 arrested this week, was secretly recorded boasting that his great-uncle had been Petrosino’s killer, according to Reuters.

<snip>

“My father’s uncle, whose name was Paolo Palazzotto … was the first to kill a cop in Palermo … Joe Petrosino, an American cop,” he says.

http://www.euronews.com/2014/06/23/italian-police-solve-century-old-mafia-killing/

You'd never peg him for a member, either. Very old school--no outward display of wealth, plain, almost shabby clothes, a serviceable car, lived with his mother...but he was one of the richest SOBs in bella Napoli.