Here in San Francisco, there are plenty of crime that goes around, but I think partisans find ways to keep things under wrap. I read the newspaper everyday and there's always at least 1-3 killings reported on a daily basis buts is always in the innercities of Oakland or Richmond and many of the victims as well as suspects are of African-American decent. The political rationale here is that Chinatown generates revenue on a consistent basis for the city. It remains a popular stop for tourists visiting San Francisco, but because there aren't that many crimes reported doesn't mean its not going on.

As for the structure, its more of an organized crime than it is some gun-wielding maniacs running around. The structure is very much like the Italian mafia. Each family has one top leader or Lo-Dai (Boss). Next to him is his right hand man (underboss or consigliere). Under them are a bunch of (Dai Gohs) leaders of gangs that are designated a certain district of the city and you have the underlings (Sai-Lo's). Allen Leung was their most recent Boss but he was murdered two years ago. I don't know who has taken his spot.

http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2006/04/08/MNGE9I686C1.DTL