Gore and More discussion

Hi, I am trying to remember the name of this really good (in my opinion) Dean Koontz was the author.

What I remember from the story:

There was a woman involved in the story and I believe she was attacked by a man. I think the man (one of the main characters) worked at her job or somewhere she was familiar with. She accused this man of attacking her , but no one really believed her because he was miles and miles away at some sort of event. He had a verified alibi, which was strange because she was 100% sure he was the man.

Anyway later in the story it is revelaed that the man has a secret twin brother. They are both serial murderer rapists. They were a secret pregnancy at birth and the birth mother's father told everyone they were adopting a relatives child. When the birth mother ended up giving birth, it was twins. So their identities were hidden, and no one was to know there were two of them. I think she used to abuse them and beat them on their private areas, or something like that. She would tell them they are part monster or demon and gave them a complex. They attack and rape women that resemble that birth mother, which was the reason they attacked the lady I mentioned in the beginning. It was supposedly because they truly believed they were part demon and couldn't themselves to anyone. They are caught in the end. I was telling my niece about the story but I cannot remember the name of the book. I have scoured the internet using the terms serial killer twins or secret twin brother murderes who kill woman who resemble their mother but no luck. Please HELP if you can by telling me the name of the book. Thank you!

Whispers had the whole twin twist to it. I'm not 100% sure about all of that because it's been a while, but whispers had a lot of the family'm only stuff you were mentioning.

Whispers