I saw this movie around 2008 or 2009, pretty sure on Lifetime. The dad in the movie is an alcoholic, and goes out one night on his boat drunk. He ends up dying, and the police think it's a suicide. In the end, it turns out the daughter killed the dad (I think he was trying to rape her) and her and the mom cover it up to make it look like a suicide. I also remember there was something with a pearl necklace, letters, and the mom had a new boyfriend after the husbands death?? Thanks!