In my opinion, the most clamorous case of the mafia attacking the law enforcement in America is the case of Rosario Borgio in Akron, Ohio, who launched a terroristic campaign against the police in 1918 after he wasn't able to buy them for some reason (very strange considering the fact he managed to buy local politicians).
Willie Marfeo to Henry Tameleo:
1) "You people want a loaf of bread and you throw the crumbs back. Well, fuck you. I ain't closing down."
2) "Get out of here, old man. Go tell Raymond to go shit in his hat. We're not giving you anything."
