A house fire that claimed the lives of two young children is likely to have been caused by an electrical fault in a first-floor bedroom, investigators have said.
Emergency services were called to the blaze at the three-storey house in Buttercup Avenue in Eynesbury, Cambridgeshire, on Thursday morning.
Cambridgeshire Police said it is believed the fire broke out at around 7am.
A three-year-old boy and a seven-year-old girl were pronounced dead at the scene.
Their 35-year-old mother was taken to hospital with life-changing injuries after she leapt from a second-floor window to escape the inferno.
Her partner, a 46-year-old man, suffered minor injuries.
Police said in a statement: "An investigation into the fire has concluded the most probable cause was an electrical fault in a first-floor bedroom at the property.
"There are no suspicious circumstances and a file is in the process of being handed to the coroner where police involvement will end."
Floral tributes and soft toys have been left on a verge near the house.
A message left with a teddy bear read: "We have no words. So heartbroken. Hope you are all in a better place. XXX."
Windows on the terraced home's second and third floors are completely burnt-out, with the rooms inside blackened and guttering melted away.
The house is on a modern estate near St Neots, with many homes decorated for Christmas – including a festive wreath on one immediate neighbour's door.
It is understood the electrical fault was not caused by Christmas lights or decorations.
Neighbour Charles Cooper, 30, said: "The flames went up fairly swiftly.
"By the time my wife and I woke up the firefighters had already arrived.
"It took a good three or four hours before the smoke abated.
"The flames were coming out of the top window."
He said he did not know the family to speak to but "we would give them a wave".
He added: "I've seen the children playing in the garden.
"Everyone's perfectly polite and pleasant but it's not the sort of place we all get together on a regular basis."
Neighbour Peter Kellythorn, 40, said there was a smell "like something might be smouldering" when he awoke on Thursday.
"I got dressed, came outside and there was smoke billowing out from the back window," he said.
He added a satellite dish on the house appeared to have melted, and said: "The heat – it doesn't bear thinking about. It's awful.
"We hoped everyone had got out.
"They're fairly new houses and they're all fitted with fire alarms and things.
"It's just awful."
A GoFundMe page set up by a neighbour with a target of raising £1,000 for the family had reached more than £3,000 by Friday lunchtime.