We don't have the stats for those who survived yet, but as far as homicides:
Victims:
37% had previous weapons charges
55% had previous drug charges
60% had previous crimes against persons charges
Suspects (when known):
50% had previous weapons charges
60% had previous drug charges
74% had previous crimes against persons charges
121 from 144 due to gunshots (4 causes of death intentionally withheld for investigatory reasons)
Primary reasons for homicide (when known) in order:
Drug related
Argument related (which is often drug/gang related)
Robbery related (which is often actually drug related)
Unknown
Revenge (which is often drug/gang related)
Domestic
The first 3 are the vast majority.