“It is possible, but seems unlikely, as the black homicide numbers are a significant majority of the homicides in the United States.”
FBI UCR data:
Murder Victims by Race (2011)
White 5,825
Black 6,329
Race of Victim by Race of Offender (2011)
Victim White, Offender White 2,630; Offender Black 448; other and unknown 94.
Victim Black, Offender White 193; Offender Black 2,447; other and unknown 55.
Justifiable Homicide by Private Citizen with Weapon.
FBI definition in the UCR:
http://gunwatch.blogspot.com/2012/12/how-fbi-uniform-crime-report-defines.html
The numbers are deliberately skewed to inflate “white” homicide offenders by including non-black hispanics as “white”.
If you take out the black and hispanic subcultures in the U.S., the homicide rate falls in the middle of those of Europe:
http://gunwatch.blogspot.com/2013/01/european-murder-rates-compared-to.html