Soldato
Out of morbid curiosity - does the colour matter? It may well be a superficial detail, of potential use for identification to the police but that's about it - if I get mugged by someone then I'm really not concerned about their skin colour, their background, their socio-economic status, their religious views or anything much else, their defining feature for me is that they are a criminal who has just mugged me but I wouldn't presume that similarities in appearance between them and anyone else tells me anything about whether people who look like that are also likely to commit a crime against me.
Indeed it does not matter, I just find it hilarious how so many people jump on the fact you mention ethnicity these days. OMG YOU SAID BLACK. Yeah...They were black!!
I actually seem to think you are more likely to describe someones skin colour if its different to your own. I believe a black person for instance is more likely to describe a group of all whites as exactly that.
Its not really prejudice, just a strange way we separate groups in general chatter