I spent a summer after high school living with my then-girlfriend at her parent's house in Canoga Park. It was both fun and memorable, especially for an unworldly kid from Virginia, and especially for one who had never before been to Southern California.
That said, I have somewhat detailed memories of Canoga Park. Which was not probably the abolute highlight of the experience. And, among other things, recall seeing the Canoga Park Wienerschnitzel -- a chain, among others, of which this East Coast boy had never heard a peep.
Based upon this (admittedly long-ago) experience, I can say fairly confidently that it surprised me not in the least that there were multiple gang-related murders at this establishment.
Check out the opinion for a fairly good discussion (by both the majority and the dissent) of the nature of gangs in the modern era as well as the legal implications of routine gang-on-gang confrontations. It's an interesting tale. Even for those who've never been to this particular Wienerschnitzel.