Those are the ones who aren't suspected or caught.
In Chicago, most of the homicides are committed by "race unknown" with black victims.
You could probably, in all honesty, add 95% of the "unknowns" to the black column, giving them about 75% of all homicides rather than 60%.
Given the majority of the "unknowns" happen in black dominated parts of the city and are typically gang related where no one's caught, I'd say you're 100% correct.
BTW: Chicago PD's clearance rate on murders is @ 15%. If you want to kill someone and not get caught, bring them to Chicago. I'm NOT kidding about 15% clearance rate.