Bloodline (2007)

Synopsis: Nate and Marcus are half brothers born and raised in the ghetto of South Florida by their unstable single mother. During a playground fight Marcus defends his brother by stabbing a bully who is threatening his brother's life. When Marcus' father finds out about his son's behavior he removes Marcus from his mother's home. Years later the brothers are reunited on the streets of Miami but on different sides of the law! Marcus has become a police officer while Nate has become a local drug dealer. The promise to stay brothers forever puts Nate and Marcus relationship to the test.   Source: Amazon.com