It is thought Fiona Adams jumped on to a trampoline to escape the fire
Detectives are continuing to question a 17-year-old boy after two young children were killed in a "suspicious" house fire in a Derbyshire town.
A woman, 23, and her baby son escaped from a first floor window, but a girl, five, and a boy, two, died in the fire in Edale Way in Buxton on Friday.
The eight-month-old baby and mother, named locally as Fiona Adams, are in a stable condition in hospital.
Police said the teenager was arrested in the early hours of Saturday.
Post-mortem examinations were due to take place on the two children on Sunday but officers said formal identification had yet to take place.
The mother is currently in a specialist burns unit at Wythenshawe Hospital in Manchester.
It is thought she jumped with the baby from a rear window on to a trampoline in the garden.
The baby is being treated in Royal Manchester Children's Hospital.
Police have appealed to residents who took photographs or videos of the fire to contact them.
Assistant Chief Constable Steve Cotterill, from Derbyshire Police, said: "We have received scores of calls and approaches by people with information and for that I am very grateful.
"I'd urge anyone who may have photographs or video footage of the scene of the fire either prior to, during or after the incident to get in touch with us to help us build up a full picture of what has happened.
"The investigation at the house continues today to pinpoint the cause of the fire and I would like to reassure local people we are doing everything we can to get to the bottom of this matter."
Derbyshire Fire and Rescue Service and Derbyshire Police are conducting a joint investigation into the fire, which is being treated as suspicious.
Mr Cotterill said the fire was being treated as suspicious because there was no apparent obvious accidental cause.
Police had previously been called to the house at 2245 BST on Friday after reports of noise and nuisance in the back garden.
Officers conducted a search and found that garden furniture had been disturbed but nothing else was found.
Mr Cotterill said because police had had contact with the family before the fire had begun, the incident had been referred to the Independent Police Complaints Commission.