@CharlesJBudde: So here's a table from the CDC that shows causes of death for black males, by age. As you can see, homicide is the leading cause of death for ages 15-24. www.cdc.gov
For comparison, here's a similar table for white men: www.cdc.gov
We know that for most homicides, victims know their assailant. We also know that at least in the United States, people's social circles tend to be made up of people who they identify with, who look like them. So the whole "black on black crime" soundbyte we hear so often is really a red herring.
That said: The task of bringing down homicides is often left to local police departments. There are certainly nonoprofits at work, and some federal agencies, like the US Department of Housing and Urban Development, have put out grants to help local governments reduce a lot of the underlying causes of violence: concentrated poverty, unemployment, etc.