Ellie Butler's grandfather described the "heartbreaking" day she was sent back to live with her father, who murdered her 11 months later.
The six-year-old girl was beaten to death by Ben Butler at their family home in Sutton, south London, in October 2013.
She had been placed in the care of her grandparents as a baby after Butler was accused of shaking her.
Ellie was returned to live with her birth parents in November 2012 after a ruling by Mrs Justice Hogg in the Family Division of the High Court.
Her grandfather Neal Gray described the day she was taken away from him and his wife Linda in a statement read to South London Coroner's Court.
He dabbed his eyes as his evidence was read and asked to leave the hearing for a few minutes to compose himself.
"The day Ellie left us was simply heartbreaking. She had no idea what was going on," he said.
"She had been told she was having a sleepover at her mum and dad's.
"We told Ellie that we loved her and would see her tomorrow when she came home - but she never did."
He added: "Linda and I felt we had suffered a bereavement and nobody cared. It was really hard to come to terms with our loss."
Mr Gray said the social workers at Services for Children (S4C) had "failed in their duty" to Ellie.
"S4C lost sight and started to pander to the parents' unreasonable wants and demands," he added.
He told the inquest that Ellie repeatedly said she wanted to continue living with her grandparents but her wishes were ignored.
Mr and Mrs Gray also had concerns about her being returned to her birth parents but they were also not listened to.
"We felt utterly helpless and unsupported," he added.
"Linda was fearful of the risk posed by the parents, chillingly her fears turned out to be justified but no one would listen to us."
Mr Gray described Ellie as a "beautiful girl" who was "kind, happy, cheerful and bright".
"I am proud to say that Ellie was my granddaughter," he added.
"We loved her to bits."
Her mother Jennie Gray was convicted of child cruelty and perverting the course of justice and sentenced to 42 months' imprisonment.
Butler is serving a life sentence with a minimum term of 23 years after he was convicted of Ellie's murder by a jury at the Old Bailey.
They both followed the proceedings via video links and repeatedly interrupted as witness Mr Gray's statement was read to the coroner.
Butler denied killing his daughter while giving evidence over the link from prison.
"I didn't cause Ellie to die, I didn't cause any injury to Ellie at all," he added.
"I believe I have got some proof and this is far from over, that's the message to you all - this is far from over."
Social worker Steven Atherton, of Services for Children, admitted that the system had failed Ellie.
"We were part of a system that failed this little girl," he said.
He added that Ellie was "emotionally struggling" with the move from her grandparents to her birth parents.
The inquest is examining whether there were failures on the part of the authorities with regard to Ellie's murder, including the sharing of information, co-operation and communication between organisations.