One need only look at the homicide statistics from the U.S. Department of Justice, select “by race of perpetrator” and the essence of the problem kinda just sits there staring you in the face. The last time I looked at a time-series of this data, when you looked at the young black male homicide rate (by race of perpetrator) it was slightly more than 8x that of non-black, non-asians (i.e. all Caucasians) of the same age range.
Here are examples that make your point. The following figures are from city-data.com. The murder rate is for 2009. Note that El Paso is 80% hispanic and is one of the safest cities in the US.
WashDC murder rate 23.8/100,000; black pop. 52.8%
Philadelphia murder 19.5/100,000 black pop. 41.5%
New York murder rate 5.6/100,000; black pop. 23%
San Jose murder rate 2.9/100,000; black pop. 2.6%; hispanic 32.6%
El Paso murder rate 1.9/100,000; black pop. 2.6% hispanic 80.5%