Carol's Letter is found in Silent Hill: Downpour, on level A2 down a flooded hallway, on a side table in the Overlook Penitentiary. This is a letter from Carol Pendleton; Murphy Pendleton's wife. It's clear from the letter that she was angry and frustrated, blaming Murphy for the death of their son, Charlie Pendleton. This letter is probably one of the main reasons and a catalyst for Murphy's deep feelings of guilt.
Forgiveness? You have the balls to ask me for FORGIVENESS? How can I possibly forgive you when you've destroyed everything I had left in this world? Every time I look at you, all I can see is his face. I only ever asked one thing of you, and that was to be a good father to our son. You failed me, Murphy. You failed me, and you failed Charlie, and now there's no way we'll ever have him back.
Don't call me. Don't write. I never want to see you again.