Also, think of all the paperwork!In b4 the police dont give a fuck anymore since the dead were hooligans anyway.
In chapter 45, it's mentioned that Paisen's dad (or at least one of his men) helped him out because he doesn't want to be known as the father of a murderer, considering the huge scale of business he's running in the underworld. The Japanese apparently take these things seriously, at least in anime/manga as far as I know, that even being related to a murderer could make society relentlessly dogpile you (see Tobio's brief daydream in chapter 13).I dont understand why would Paisen and Maru decide to do that too.