Hunted because of a secret

This was several years ago. I'm puzzled why it popped into my head recently. I have a very very brief collection of this fiction book. From the back of the book, I remember this much... A man saw an accident. He approached the victim and the victim was dying. The dying shared a secret with the man. Because of this secret, the man was hunted.

There are SO... many books to read. I cant explain but 'this book' is chewing my time & mental.