I asked my husband about this, as he would know. He said that naturally Mr. Narita had contacts with the Yakuza, anyone who runs any sort of night club business must have mafia contacts in order to survive and for protection, it's the way it is here in Japan.
But he himself wasn't in the mafia. And most likely, he doesn't have any contacts in the Japanese mafia anymore since he hasn't had his night club business for a long time.
It's not really something though you want to ask him or even talk about openly in Japan, it can lead to big big trouble. The Yakuza are nasty and vicious here. The best thing is to ignore it, or not let yourself get involved in a sort of business that would require Mafia involvement. I know one female member who got beat up by the local mafia for balooning during a festival and not paying fees to the local guys.
A tatoo in Japan is a mafia sign, generally only the yakuza have tatoos, and some of them are pretty awesome, body covering tatoos. Nowadays it's getting more popular for the youth to get tatoos, but I suspect that there are certain places and certain types of tatoos they know belong to the Yakuza and the ordinary person doesn't get.
Back to Mr N. Yes, he had contacts in the Mafia, but he himself was not part of the mafia.