The woman arrested on suspicion of murder after an 18-month-old boy fell from the window of a sixth-floor tower block has been named locally as Gemma Procter.
The 23-year-old remains in police custody after officers were called to Barkerend Road, Bradford, on Saturday afternoon (21 October) following a report that a child had suffered life-threatening injuries.
It quickly became clear the 18-month-old boy had died, said West Yorkshire Police. Procter, who has been arrested, is receiving a medical assessment in custody.
Shocked residents spoke about the terrifying moment they saw the naked baby fall to his death.
Witness Danuta Tomaszewicz, 59, had been on her phone, looking out of the window from her first floor flat when she noticed the child on the ground below. Tomaszewicz said that at first thought the figure was a doll.
Her niece Monika Tomaszewicz added: "She realised it was a real baby when she saw he was trying to catch his breath and his belly was moving.
"She screamed for help and her husband and his friend ran downstairs. The friend took his shirt off because the baby was naked."
Andrew White, 53, lives on the same floor as the flat from which the baby fell. White said a couple with two young children live at the address.
He added: "They are a nice young couple who keep themselves to themselves which is normal here."
Another resident on the same landing of the where the baby fell said: "There's quite a high turnover of people in these flats, you wouldn't necessarily know your neighbours. I just keep to myself."
Detective Superintendent Nick Wallen said: "This is clearly an extremely traumatic incident and specially trained officers are working to support the child's family members and those who witnessed what took place.
"It is no exaggeration to say those who witnessed this incident will have been deeply traumatised by what they saw.
"A 23-year-old woman has been arrested on suspicion of murder in connection with the baby's fall and she is currently receiving medical assessment in custody.
West Yorkshire Police said they are not looking for anyone else in connection with the incident but have appealed for witnesses or anyone with information to come forward.