Yes, but the way you describe the passage in the novel (which I still have not read)...Sonny tells Vito years later that he saw the whole Fanucci killing. Is lettle Santino's presence made known while reading that in the book?

Also, by the time The Godfather takes place, Sonny is already working for and with his father; there would be no reason or place to even fit in that 'confession' that he witnessed what Vito did.

Of course...those who endlessly argue for a GFIV 'prequel' might insist that this would be a good scene between Vito and a Santino in, say his early 20's !!!

Apple