[TOMT][Movie] Walking on a beach, note floating in the water...

Try to help us out! Friend came to my group of friends at the pub and asked about a movie: we got the following details (very vague, and didn't ring any bells) :

There is a scene where an actor is walking along the beach when they find a picture of a fish floating in the water, drawn with crayon.

The movie is a murder mystery/thriller, and the main actor is a "De Niro type".

There is a gazebo at some point, someone gets buried in concrete..

I know there's not much to go on here. It's all the details we were given. Movie was several years (10+ years) old. Any thoughts, anyone?!