They used to kill rats, in the era of Frank Costello and Luciano, they murdered several guys who were even held up in a safehouse filled with cops. They always managed, but as mentioned earlyer, it's easier to solve murders today, government isn't as corrupt and heat-bill is too damn expensive.

I don't think Leonetti or anyone is really in danger, the main reason why Leonetti is hiding his faces is so that his new neighbors won't recognize him.