Online
It would be interesting to see the breakdown of victims known to the perpetrator, although I am not certain that information is necessarily available.
This data is somewhat dated now, but the breakdown here is interesting:
Crime Statistics Australia | Crime Statistics Australia
www.crimestats.aic.gov.au
Only 10% of victims were strangers to the perpetrator and only 13% of the overall number of homicides occurred by gunshot wound. I imagine the numbers might be slightly different in NOLA/the US.
The vast majority of murders in New Orleans are by gunshot and involve young male African Americans - most commonly arising from drug trade and retaliation. So the killer and victim have a relationship of some sort.