Chicago’s Real Crime Story
Sad facts from America’s most segregated city:
In Chicago, blacks, at least 35 percent of the population, commit 76 percent of all homicides; whites, about 28 percent of the population, commit 4 percent, and Hispanics, 30 percent of the population, commit 19 percent. The most significant difference between these demographic groups is family structure. In Cook County—which includes both Chicago and some of its suburbs and probably therefore contains a higher proportion of middle-class black families than the city proper—79 percent of all black children were born out of wedlock in 2003, compared with 15 percent of white children.

Is it the family structure that causes the crime, the crime that causes the family structure issues, or a third variable that causes both?
Difficult problems, difficult solutions.
Yeah, there’s no easy answer on that one – the other evidence I’ve seen about (relative) stability in two parent homes would point me to your first option, but it’s also clearly the second.