Milly Dowler's father was a suspect in her disappearance after police found bondage material at their family home in Surrey, the Old Bailey has heard.
Bob Dowler broke down in tears while giving evidence in the trial of Levi Bellfield, who is accused of murdering the 13-year-old.
Notes by Milly in which she said she was unhappy, were read out in court.
Bellfield, 42, denies abducting and murdering Milly and attempting to kidnap another girl in March 2002.
The court heard that police had informed Mr Dowler he was a suspect after his daughter disappeared.
'I am sorry'
He had told officers that his daughter had found a bondage magazine in his bedroom.
But he denied having anything to do with his daughter's disappearance.
Defending Bellfield, Jeffrey Samuels QC cross-examined Mr Dowler, an IT consultant, and asked whether it was right that Mr Dowler became the focus of the police inquiries for a time.
Mr Dowler answered: "That is correct."
He also said he had considered this to be a waste of time.
"I was very concerned because I knew if they focused on me, they need[ed] to be focused on someone else," he said.
The court heard how a poem and letter had been found in Milly's bedroom.
Mr Samuels read out part of a letter which said: "All they do is slag me off and force everyone else against me.
"I am not pretty or fit, what do they have that I haven't? Let's face it, I am just totally shit."
A second note read: "Dear daddy and my beautiful mummy, by the time you find this letter I will be gone. It would be best for you to try to forget me. I will always love you.
"I am sorry but lots of love, your little disappointment."
In one of the notes, Milly wrote how a friend Jess her helped through "this whole dad thing", jurors heard.
Mr Dowler said he could only think she was referring to "something in the bottom drawer of a chest of drawers".
He said: "In looking for the item she pulled the whole drawer out and underneath the drawer discovered a pornographic magazine."
When asked to describe the magazine, Mr Dowler said it was "probably extreme pornographic material, a fetish nature, latex and bondage".
He told the court other porn had been found in the house by police, including videos in the lounge, and bondage equipment including a rubber hood and ball in the loft.
More porn magazines had been marked in a way that indicated he had made inquiries or had used services, jurors heard.
Mr Dowler was asked what impact the items would have had on his daughter and said she would have become "most distressed".
He agreed he had told police it would have been "a complete betrayal as a father".
But he also told officers he had "no involvement whatsoever" in Milly's disappearance, the court heard.
Sally Dowler, Milly's mother, told the court she thought her daughter had found the magazine about two months previously.
She said: "I said to her: 'It doesn't mean that daddy doesn't love me'. I am sorry she had found it."
The prosecution claims Bellfield tried to abduct Rachel Cowles, who was 11 years old, on 20 March 2002.
It is alleged he drove off after trying to abduct the girl when he saw a police car and that he went on to murder Milly the next day.
Milly disappeared on 21 March 2002 in Station Avenue, Walton-on-Thames, near Bellfield's home in Collingwood Place.
The jury has been told she had just called her father to say she was on her way home.
Her remains were found six months later.
Bellfield, a former wheelclamper and club bouncer, was convicted at the Old Bailey in 2008 of attacks on women in west London over a period of about two years.
He was convicted of killing Marsha McDonnell, 19, in February 2003 and Amelie Delagrange, 22, in August 2004, by striking them on their heads with a blunt instrument.
In May 2004, he attempted to murder Kate Sheedy, 18, by deliberately running her over in a car.
The case was adjourned until Tuesday.