Yes, a true story, but that doesn't make it worthy of a movie. The story of the police officer addednothing to the plot; the outcome would have been the same with or without him, and many questions about him we're not addressed. The main character remains unchanged as a result of the events that occur. It ends with him robbing a bank...again.
The sign of a great story is to cause the audience to genuinely care about the characters. There was no one I really cared about.