Can you recommend me a novel like this? (details inside)

It can be of any genre (but mystery should be great), with any plot, but the basic plot should be like this: the protagonist once did (or thinks he/she did) something horrible in the past that had a tragic outcome, but no one seems to know. At the present time a certain problem arises, forcing him/her to face that past again. The story should then focus strongly on the protagonist’s inner thought and struggle to choose between keeping the past a secret and revealing it to everyone (given that the knowledge of that past can lead to a solution to the problem at the present time). I have read some stories in which one of the character encounters such situation, but mostly the protagonist who tries to uncover the truth is an outsider (the one who wasn’t involved in the past event at all). I need a story featuring the protagonist as the one who is fully involved in both the past and present events. I need to learn how to describe a character’s thought and feeling in such a situation. Can anyone recommend me a book like that?