interesting - did the level of policing drop and the crime stay down? did some people move from/to the area? were new groups formed?
people just didn't hang around the streets as much. Whether it was because it wasn't deemed acceptable generally, or whether there was something else going on (like the cops round people up or whatever) I don't know. The change was quite stark though.
The guy that was convicted of the murder was a well-known local too. For something like that to happen in a middle-class area causes a severe ego-pounding. The area becomes tainted. All of a sudden people care what happens on the streets around then cos of some superficial shit like it affecting the value of their houses, etc. Like, people start caring, but only for selfish reasons.