A mother whose four children were killed in a house fire begged to be moved to a safe house earlier that week, their family said.
Fifteen-year-old Demi Pearson, her brother Brandon, eight, and sisters Lacie, seven, and Lia, three, died following the blaze at the family's mid-terraced home in Jackson Street, Walkden, Greater Manchester, shortly after 5am on Monday.
Their mother Michelle Pearson remains in a critical condition and the family are "dreading" the day they will have to break to her the "awful news".
Claire Pearson, Michelle's sister, said: "Michelle's been unsafe in that property for months and months and the police was aware of this, and the social services was aware of this, the council was aware of this, and I'm sorry to say this but ... they've let her down, and my sister and her kids would have had a chance of survival if they did their job properly."
The children's grandfather, Mike Pearson, added: "She said she'd actually been to the housing that week and begged them to move her to a safe house or get her out of the area ... they just refused - 'you're not at risk, you're not in danger'."
In a statement, the family said: "This week has been a whirlwind. We have been in our own bubble and our focus has been solely on our family, on our Michelle as she lies in her hospital bed.
"We are heartbroken at the death of our four babies."
They went on: "Their mum Michelle is in a critical condition.
"We are dreading the day we have to tell them the awful news about her babies.
"We hope and pray that she has the strength to pull through.
"We are asking people to keep Michelle in their thoughts, she has lost her babies and it is heart-breaking but she has a loving family who will try their best to get her through this and two older sons who adore her."
Paying tribute to the children, the family said: "Demi, such a beautiful young lady with so many friends.
"She would do anything for anyone, nothing was too much trouble.
"She had been poorly through her life but she was tough and so strong, nothing could stop her.
"She was like another mum to the younger ones, such a star."
They described Brandon as the "next Stephen Hawking" and said he and his sister Lacie were like twins.
"They were always together. You couldn't just do something with one of them, they came as a pair," the family said.
The family said Lacie was a "little diva" who loved to dance and Lia loved the TV programme Peppa Pig.
They said: "She was so cute and the older ones doted on her."
Zak Bolland, 23, Courtney Brierley, 20, and David Worrall, 25, appeared at Manchester Crown Court on Friday morning charged with the murder of the four children.
The defendants are also accused of arson with intent to endanger life and the attempted murder of the children's mother, Michelle Pearson, 35, and two juveniles who cannot be named for legal reasons.
The three were remanded in custody ahead of a plea and trial preparation hearing on March 9 and a provisional trial date was fixed for April 30.