Sarah Payne's mother claims her hoe has been targeted by burglars
Activist Dr Sara Payne took to Twitter to flag up the theft of the computer, which contained memories and details about her daughter and her charity work.
She said online that the shed at her home in Hersham, Surrey, was raided overnight on February 17, and a laptop containing countless hours of the campaigner's work was stolen.
She tweeted: "#Burgled, Please, whoever you are, I implore you to return my laptop, it has all of my Phoenix/SarahsLaw/book work on it, I'm lost without it."
She added: "Nothing I can do but start again."
Sara, 47, tweeted: "The police are here, the shed has been burgled, all of our #Phoenix equipment stolen! I just want to cry."
The burglary happened at her home in Hersham, Surrey, on the week her daughter Charlotte, 22, launched her singing career.
Activist Dr Sara Payne daughter Sarah was murdered in 2000 by Roy Whiting, pictured
Thankfully, it appears that most of her work was uploaded to a data cloud so she may not have lost everything.
Nothing I can do but start again
Activist Dr Sara Payne
Currently Sara works alongside child sex abuse survivor Shy Keenan on The Phoenix Post, who speak for those whose lives have been victimised by paedophile crimes.
She was granted an Honorary Doctorate by the Open University in 2012 in recognition of her charity work.
Sarah was abducted and murdered at just eight years old by known paedophile Roy Whiting.
Little Sarah was playing hide and seek with her brothers and sister among near her grandparents' home in West Sussex when she was abducted by the paedophile, on 1 July 2000.
Sara, who became the country's first Victims' Champion – an independent voice for the victims of crime, found the strength to fight to protect the lives and innocence of other children by campaigning vigorously in her name.
The activist took to Twitter to implore the thief to return her work
It led to Sarah's Law in the UK, which allows parents to check if someone with regular unsupervised access to their children has a criminal record for abuse.
Sara, who was awarded an MBE in 2008 for her child protection work, also founded the campaign organisation The Phoenix Post.
Surrey Police have been approached for comment.