A critically-injured woman has been arrested on suspicion of murdering her two-year-old daughter, who died after falling from a house.
The 36-year-old and the toddler were discovered in the back garden of an end-terrace house in Bradford, West Yorkshire, by a neighbour who called police and paramedics.
They appeared to have fallen from a first-floor window yesterday morning.
Both were taken to hospital but the little girl died soon afterwards.
Today, West Yorkshire Police confirmed t hey had launched a murder inquiry following the incident in Delamere Street, in the Marshfields area of the city.
Officers confirmed that the child's mother had been arrested on suspicion of murder.
The woman is understood to be in a critical condition in hospital.
People living in the quiet, residential street described their shock at what happened in the house many thought was empty.
According to reports, neighbour Mohammed Yaseen raised the alarm after he was alerted by the woman banging on a bin before he and a local window cleaner tried to help with first aid.
Another neighbour, Masood Rana, described how he witnessed the heartbreaking scene of the little girl being carried out to an ambulance.
Mr Rana, 47, said he noticed the w indow cleaner who had gone to help and his neighbour in the garden of the house when he returned from the school run yesterday.
"I went inside and, after about 10 or five minutes, I heard a sort of banging noise and I looked outside and saw the police and paramedics here," he said.
"After about 10 minutes I saw a body being carried out - a little baby - into an ambulance.
"After another five minutes or 10 minutes, there was a lady taken out of the house into an ambulance."
Mr Rana said: " It's really sad. It's a tragic incident what happened.
"I don't know if the lady's got family here. My initial thoughts go to the family. It's really sad.
"We are all shocked and we're all asking each other 'Who lives there?'."
Mr Rana said he and his neighbours believed the house was empty and his attention was drawn to the window cleaner and neighbour because he thought they might be prospective buyers.
"As far as I knew, the last tenants had moved out of the house and the house was empty," he said.
"I was shocked that somebody was in there.
"It is sad. Everybody is shocked. I'm a father of four and my children are shocked as well."
Other neighbours said they believed the woman and the child had lived in the house for around three months.
A West Yorkshire Police spokesman said: " Police have launched a murder investigation following the death of a two-year-old girl in Bradford.
"The girl and a 36-year-old woman were found unconscious outside an address in Delamere Street at around 9.15am yesterday.
"Both were taken to hospital, but the child sadly died a short time later.
"The woman remains in hospital, where she is in a critical condition.
"A post-mortem was carried out last night, which revealed that the girl died of injuries consistent with a fall.
"A 36-year-old woman, who police can confirm is the child's mother, has been arrested on suspicion of murder."
Detective Chief Inspector Jon Morgan, added: " We are not looking for anyone else in connection with this incident, but are appealing for anyone with information to contact the police on 101 or Crimestoppers on 0800 555111."
This morning, flowers were laid outside the house, just off the busy Manchester Road in the city.
A note on one floral tribute said: "RIP Little One. Heaven's gained an angel."
Police community support officers were guarding the property today and a white forensics tent had been erected in the small back garden.
Forensics officers could be seen entering and leaving the house.
Labour councillor for Little Horton Sher Khan said the death of the unnamed youngster had shaken the community.
He said: "I've lived in that area all my life - 45 years - and it's a good community, lots of good neighbours, so this is a great shock to everyone.
"You can imagine that, when a two-year-old child dies in a street, it's a real shock for a community. It's touched everyone around here."
Mr Khan said he believed the woman and her daughter had lived in the house for a few months and had come to Bradford then from the South of England.