Its about 3 young boys playing outside and one boy gets kidnaped for a few days and gets molested then gets aways, years later they all grow up and one of the boys grows up to be a cop and another boy grows up to be a mob leader and the boy that got molested lived a regular life. The mobs daughter gets killed and the cop friend is the one that's investagating the murder. Some how the mob friend thinks that it was his friend that got molested was involed in his daughter death and ends up killing him ,to find out towards the end the cop friend goes to him telling him that the killer was the daughter boyfriend little brother.

I totally know what movie you are talking about but after the first sentence the title went out of my head! I hate it when that happens! Let me know if you figure it out.

Oh it might help if you know the actors and you can look on IMDB.com and just check the list of movies they have been in. :)

Mystic River (2003) (http://www.imdb.com/title/tt0327056/)

You're very welcome.