Oakland, California, in 1948, had about the same population as it does today, with roughly the same racial makeup (a slightly smaller hispanic community, a slightly larger Asian community) and the same mix of incomes.
In that year, there were fewer than 15 homicides in that city. Last year, there were somewhat north of 100. One-hundred-plus murders. Any ideas as to why? I'll tell you what doesn't explain it: There was little gun control in those days, and there was considerably more poverty, and the poor were poorer in both relative and absolute terms than they are today (remember, this was long before the Great Society programs of the mid 1960s.)