Ellie Butler’s grandfather vowed her death “cannot have been in vain” as he described her murderer father as a “brutal maniac” in an inquest into her death.
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 said Ellie looked like an “orphan” with dirty hair and a bruise on her face when he saw her for the last time, two days before her death.
He said Ellie’s mother Jennie Gray was “just as culpable” in her death in his evidence at South London Coroner’s Court.
“She stood by and watched that brutal maniac inflict unimaginable injuries to her children and she defended him without question or remorse,” he added in a statement.
“The true horrifying extent of the torture endured by Ellie came out as the criminal trial unfolded. I was aghast.”
He continued: “The simple fact is that she was placed at fatal risk by being returned to her parents. Her death had been avoidable.
“The circumstances surrounding it must be avoided so that lessons may be learned and other children protected in the future.
“Her death cannot have been in vain.”
Mr Gray described the day Ellie was taken away from him and his wife Linda as “heartbreaking”.
“She had no idea what was going on,” he added.
“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 said that Ellie had repeatedly said she wanted to continue living with her grandparents but her wishes were ignored.
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.”
He dabbed his eyes as his statement was read to the coroner and asked to be excused to compose himself.
Linda Gray died on the first day of Butler’s trial for Ellie’s murder.
He is serving a life sentence with a minimum term of 23 years after he was convicted by a jury at the Old Bailey.
Jennie Gray was convicted of child cruelty and perverting the course of justice and sentenced to 42 months’ imprisonment.
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 prison link.
“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.”
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.
Dame Linda Dobbs, a retired high court judge who is sitting as coroner for the inquest, is due to announce her determination on April 10.