Warnings about murdered six-year-old Arthur Labinjo-Hughes were ignored, his grandfather has said.
Arthur’s stepmother Emma Tustin, 32, was found guilty of his murder at Coventry Crown Court on Friday and sentenced to jail for life with a minimum term of 29 years.
Thomas Hughes, his father, 29, was jailed for 21 years for manslaughter.
Arthur’s maternal grandfather, Peter Halcrow, said the boy’s other grandparents had issued warnings.
He told BBC Radio 4’s Today programme: “They’re decent people and they were very concerned. And they issued warnings that were ignored, shall we say.”
Mr Halcrow said the couple responsible for Arthur’s death had committed a “heinous crime” by killing a “defenceless, innocent boy”.
He told the broadcaster: “I wouldn’t give them the time of day and I wouldn’t want them to see the light of day ever again.”
Arthur’s grandmother, Madeleine Halcrow, said the system which should have ensured he was safe is “broken”.
She told ITV’s Good Morning Britain: “I am angry with the inter agencies because somewhere along the line communication hasn’t been passed along.
“The old adage ‘If it isn’t broke, don’t fix it’… Well, something is broken in this system and something needs fixing.”
Discussing the jail sentences for his killers, she said: “Life should mean life. They took Arthur’s life, he’s not going to get his life back, he’s not going to have children of his own.”
She said Tustin and Hughes had shown “no remorse, no sympathy”, and branded them “depraved, sadistic, torturous, evil, calculating people”.
Arthur, from Solihull in the West Midlands, was left with an unsurvivable brain injury while in the sole care of Tustin.
She was convicted of murder by assaulting him in the hallway of her Cranmore Road home in Solihull, on 16 June 2020. He died in hospital the next day.
The trial heard Arthur’s body was covered in 130 bruises and he had previously been poisoned, starved and beaten by Tustin and his father.
Concerns were raised about his care and welfare throughout his case, it has emerged.
His uncle said he sent police pictures of his nephew’s bruises, and his grandmother had alerted social services.
Two social workers visited Arthur at home last year but said they had “no safeguarding concerns”.
A national investigation into Arthur’s death has been launched and the government has commissioned an urgent inspection of social care, health, police and probation services in Solihull.