A woman has been arrested on suspicion of murder after a baby fell to his death from a sixth-floor window.
Witnesses spoke of their desperate attempts to save the 18-month-old at a block of flats at Newcastle House in Bradford on Saturday afternoon.
Danuta Tomaszewicz said at first she thought the baby was a doll and only realised it was a real baby when she saw him trying to catch his breath.
An ambulance arrived 20 minutes later, but the baby died.
Police have arrested a 23-year-old woman who is still being held in custody.
Detective Superintendent Nick Wallen, who is leading the investigation, 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 thebaby's fall and she is currently receiving medical assessment in custody."
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.
Anyone with any information is asked to contact Bradford CID on 101.