Of the offenders for whom race was known, 53.1 percent were black, 44.6 percent were white, and 2.3 percent were of other races. The race was unknown for 4,224 offenders. (Based on Expanded Homicide Data Table 3.)
based on those percentages 2,243 of the unknown offenders are also black.
pretty outstanding job by 13% of the population, actually even far less than that when you consider black males of a certain age group. it's almost unfathomable for that small a subset to be such prolific killers.
https://ucr.fbi.gov/crime-in-the-u.s/2010/crime-in-the-u.s.-2010/offenses-known-to-law-enforcement/expanded/expandhomicidemain