Rates for what? Rates for murder and violent crime are not similar across all races. They vary significantly. In order (from highest to lowest) they tend to be as follows: Black, Hispanic, White, Asian. Coincidentally (or not), IQ tends to follow the same pattern, from lowest to highest.

Just looking at murder, blacks accounted for 52.5% of homicide offenders from 1980 to 2008. Looking at offenders per 100,000, it is 34.4 for blacks versus 4.5 for whites. http://www.bjs.gov/content/pub/pdf/htus8008.pdf

There have been many studies, not just from the arrest, sentencing, and imprisonment side. There are studies in which random people are polled and asked whether they have been victimized. It is not poverty alone. Homicide among impoverished whites is nowhere near the levels seen among blacks.