A teenage boy critically ill in hospital after a house fire which killed five of his siblings is "unlikely to survive", police said.
Duwayne Philpott, 13, has been in hospital since the fire at the family home in Victory Road, Allenton, Derby, in the early hours of last Friday.
His sister Jade Philpott, 10, and brothers John, nine, Jack, seven, Jessie, six, and five-year-old Jayden died in the blaze.
Assistant Chief Constable Steve Cotterill of Derbyshire police said: "Duwayne suffered serious injuries in the fire; tragically he is unlikely to survive.
"Mr and Mrs Philpott remain at their son's bedside and my thoughts are with them at this distressing time."
The children were asleep in their beds upstairs in the house when the fire broke out at the pebble-dashed semi-detached home.
The children's father, Mick Philpott, made a "valiant" attempt to save them, police said.
Said to be the father of 17 children, Mr Philpott hit the headlines after demanding a larger house to share with his wife Mairead, girlfriend, Lisa, and eight offspring.
A 28-year-old woman and 38-year-old man, both from Derby, were arrested by officers investigating the deaths but were later released without charge.
ACC Cotterill added: "This investigation is still at an early stage and it should be stressed that we have not yet had the opportunity to speak to Mr and Mrs Philpott properly because they've been caring for their son in Birmingham."