The average number of crimes (violent + property) stateside is 10m per year*. The average offender has about 40 years of crime in him - mid-teens to mid-50's. 40 years of crime = 400m crimes. Assuming that 1 individual is on average responsible for 40 crimes, that means 10m perps. Roughly half of those perps will be black - 5m - based on historical stats about the racial distribution of crime. This is why it is estimated that 1/3 of the male black population has been through the criminal justice system. And it is why the black community supports its criminals and attempts to get them off every chance it gets - the alternative is to have many more of them serving time in prison or being executed for heinous crimes like this one.
* It's actually more, but I'm rounding down.