To Kill a Mocking... Guy

This movie starts with a bunch of small children talking about what they want to do when they grow up. After several different responses we finally come to William our main character, who says that he wants to be a serial killer. We then see several different shots of William as he is growing up, sitting in front of the tv watching a news report about a serial killer, reading a stack of books in the library about different murder cases, reading an anatomy book and making different cuts on a dummy, and he does various other things to prepare him to be a world class serial killer. Then he plans out the perfect murder to start his career as a serial killer but he is unable to follow through with it. He just can't bring himself to kill someone. William gets really depressed and doesn't know what to do with his life because he can't be what he always wanted to be. Then one day William sees an ad on tv offering a reward for any information leading to the arrest of a serial killer. William thinks that he will be able to solve the case because he knows so much about serial killing. But as he gets deeper and deeper into the investigation William realizes that the serial killer is using all of Williams methods and plans, and the serial killer realizes that someone is on his trail. So it becomes a contest to see who can out serial kill the other. When things get dangerous will William finally be able to overcome his fears and murder someone dead?