Board Thread:Manga Discussion/@comment-784068-20140630215917/@comment-784068-20140718225858

The fact that Diavolo's mother was found buried alive with her tongue cut out, though she was seen with him, and many point fingers at Diavolo himself for doing it, I'm fairly sure that was Santana's doing too. That night's events were also plenty vauge as well- It's not really known what happened nor who burnt down the apartment and killed everyone, right?

I hypothesize that Santana made his way back to Italy to see how his "wife" and "son" were up to. When he heard that his wife revealed the truth too soon without him, or was to leave him, he snapped and killed her. When they found the corpse, Santana then killed the priest and the boarders of the apartment, leaving only Diavolo alive. Soon after, Diavolo was told the truth by Santana and was then driven to seize power for the revival of a new master race, or so I guess.