Excerpt from the victim's diary.

20th December

I'm certain that something's going on with my sister.

I heard screaming again last night and followed her outside. She went into the woods which I found utterly creepy but that wasn't the worst part.

When I found her she was staring down at her hands blankly - they were covered in blood. When she looked at me it was as if she was a stranger - she didn't recognise me.

She's been showing no emotion all day, even when we found out about the newest murders. Maybe if I stay by her she'll tell me what's going on and I can help her.