Another movie who I can't remember the name of!

It's about a boy who has been kidnapped when he was little. The abductors raised him as there own child, he believes that. Later ( I think he is 18 or something) he founds his picuters in old papers and on a old milk carton. Then he came after the truth, he was kidnapped.

I don't know the end anymore, but I hope someone knows this movie. Oh and it was a true story, I believe!