Transcript for Steven Powell Diaries: 'I Can Hardly Control Myself'
Susan was very very sexual with me. It was a year ago that Steven Powell shocked the world by claiming that he was having a sexually charged relationship with daughter in -- Susan. We interacted and a lot of sexual ways because. Susan enjoys doing that I enjoyed. Her family denies it. Saying she felt uneasy around now detectives say this perverse relationship came to light as they investigated Susan's disappearance from her Utah home in December of 2009. Investigators came across Stephen -- diaries detailing his obsession weather and Powell was quite prolific there were more than 2300 pages of writing in seventeen of these spiral notebooks. He wrote the fact is I can hardly control myself when it comes to her. He di -- -- like to photograph Susan when she wasn't watching. There are dozens of photos of Susan some innocent but many -- -- -- -- legs and feet. -- even admits going so far as to using a mirror under the bathroom door and then feeling guilty about it saying. This represents the first time I've mentioned that issues and what might be considered social Catholic. I mean who looks under the bathroom door with a mirror but just before Susan disappeared the journal entries and photos stopped there was no mention of what happened to -- There's nothing in the diary it's going to leave anybody anywhere to try and find Susan's body. This just disturbing rating. At Susan's family believes Stephen knows what happened. I'm sure he knows where -- Us or I've I believe he has very good idea where he is that he doesn't -- the exact spot. If Stephen knows he's not telling he said nothing to police or anyone else since his arrest and conviction from terrorism of two neighbor girls. -- coverage -- for news.
This transcript has been automatically generated and may not be 100% accurate.