I saw this movie before the year 2002. It is about 2 dirty cops (one white and the other black) who killed someone and blame it on a homeless man who was usually walking down the street with his shopping cart full of junk. Once the authorities stared to prosecute the homeless man his family recognized him on the TV, it turned out that the homeless men was a famous doctor who got depressed after his wife and child died and turned himself into a alcoholic. Now his family (the homeless man) whose is rich and powerful are fighting for him in court and eventually the 2 dirty cops will be uncovered.

Initially I thought that one of the dirty cops was Wesley Snipes but I've been looking at all his movies and I can't find it.

Gang Related (http://en.wikipedia.org/wiki/Gang_Related)