The father of murdered schoolgirl Sarah Payne has been found dead at his home in Kent.
Michael Payne, 45, was discovered at his home in Brishing Lane, Maidstone, on Monday night.
Kent Police have not identified the occupant of the property but said the death was not suspicious.
Mr Payne's eight-year-old daughter was abducted and killed by convicted paedophile Roy Whiting in West Sussex in 2000.
His daughter Charlotte posted a picture of her father on Facebook alongside a message saying she was "heartbroken".
"No matter what happened and how many mistakes we all made you will always be my daddy," she wrote.
She later added: "I'm sorry I couldn't save you dad. I hope you have finally found your peace and happiness."
Duncan Kennedy, news correspondent
Michael Payne was a father crushed by agony. A parent consumed by grief.
When his eight-year-old daughter Sarah was abducted in July 2000 his world collapsed.
She was found dead in West Sussex 17 days later, murdered by Roy Whiting - a paedophile now serving life in jail - but it was a term that gave Michael only temporary escape from his demons.
With his wife Sara, Michael found brief solace and purpose in campaigning for Sarah's Law, giving people greater information about sex offenders, but he began drinking heavily and the marriage collapsed.
He later said he had failed to protect his own daughter.
He had tried to come to terms with his suffocating loss, but in the end he was consumed.
Her brother Lee wrote: "Dad, you had your demons and troubles but you had a good heart and was a decent man! I hope now you have found peace at last! RIP, you will be missed. We are all heartbroken."
Ex-senior detective Martyn Underhill, who was the deputy senior investigating officer during Sussex Police's Sarah Payne inquiry, said Mr Payne could "walk with Sarah now".
Mr Underhill, now the police and crime commissioner for Dorset, said: "I was honoured to have known him. He battled his demons.
"But all he ever wanted to do was to see his daughter again. When Sarah went, it destroyed Michael as well."
Mr Payne split from his wife Sara in 2003 after 18 years together, blaming the difficulties of coping with the loss of their daughter.
In December 2011, he was jailed for 16 months after admitting attacking his brother with a glass after they had both drunk a large amount of alcohol.
The court heard how he had developed a drink problem after the murder of his daughter by Whiting.
In a message on Twitter, Mrs Payne thanked her 3,800-plus followers for their kindness and understanding.
Fellow child protection campaigner Shy Keenan, a close friend of Mrs Payne, tweeted: "Sara thanks you all (more than she can say right now) for your love, kindness and understanding at this very painful time in their lives."
And she wrote: "Sara wants to be left alone to care for her grief-stricken family and respectfully requests that the media leave her and her children alone."
Whiting was convicted in 2001 of the abduction and murder of Sarah and sentenced to life imprisonment.
Sarah, who lived in Hersham, Surrey, disappeared from a cornfield near the home of her paternal grandparents, Terence and Lesley Payne.
Her body was found on 17 July in a field near Pulborough, some 15 miles from Kingston Gorse in West Sussex where she had disappeared.