A man witness someone being killed on a playground near some apartments. He has to try to escape them by going through the apartment. No one would help him except a black family that let's him go through their apart...Thanks!
I believe that's how The Dream Team (1989) starts. Even though it's billed as a comedy, it features a violent murder that kicks off the plot.
Actually, now that I've had time to think about it, your movie is almost certainly Judgement Night, starring Emilio Esteves. Galyn Gorg plays a member of the black family who helps him.
http://www.imdb.com/title/tt0107286/
Thanks, I will check it.