Of course, that's not the only real life criminal org I know of though.You know those two are based on real stories and people. Pretty disturbing actually. Good films though.
One of my dad's friend told me he saw knives fight at the street in the 80s and one of the gang member's ear got chopped off, with hands covering the head asking his "boss" for help.
Dad (a real estate agent) also heard a gang boss buying up distressed properties with squatter tenant and how the gang boss bragged about the "persuasion" he use to evict tenants. He didn't know the buyer of course, only representing the seller who lost his shirt due to the squatter tenant.
Uncle, when going to court trying to sue tenant for the missing rent, got a lot of "offers" from gang members to help with "collection" services. He declined out of ethical reason.