Bienvenu, Charlu!
Joe Valachi was an American Mafioso who went to prison on a drug conviction. His boss, the Mafia Don Vito Genovese, also was in the same prison, also on a drug conviction. Valachi believed that Genovese ordered another prisoner to kill him, so he killed the other prisoner first. Now Valachi was facing a murder charge. So he became an informer for the government. He agreed to testify before a committee of the US Senate, where he revealed what he knew about the Mafia. Much of his testimony represented new information to most Americans.
If you go to this site:
http://www.gangrule.com/gallery/maps.html
and scroll to the bottom, you will see the organization charts of the various Mafia families as they were presented at the Valachi hearings in the US Senate.