An 11-month-old baby girl who died from multiple stab wounds at a flat in Abergavenny has been identified by Gwent Police.
Officers carried out heart massage on Harley Ruck at the flat in the Monmouthshire town but she was pronounced dead.
Her 22-year-old mother was arrested on suspicion of murder and is being held under the Mental Health Act.
Harley's family have paid tribute to her.
In a statement issued through Gwent Police, the baby's family said: "In loving memory of Harley Roxy Ruck.
"In the event of a horrific tragedy to our beautiful, happy, loving little daughter, grand-daughter, [great granddaughter] niece and cousin who was loved dearly and will be sadly missed by all around her, especially by her lost heartbroken mum."
Police were called to a flat at St David's Road at about 0530 GMT on Saturday carried out heart massage on the girl but she was later pronounced dead by paramedics.
Initial results of a post mortem examination have established that the baby died from multiple stab wounds.
Detectives have described the death as a "tragic" and "domestic incident".
A Gwent Police spokesperson said the woman is being detained under the provisions of the Mental Health Act and is undergoing medical assessment.
Officers have confirmed that the woman was alone in the flat with the child at the time.
They have said they are not looking for anyone else in connection with the death.
Inquiries are continuing in the area and forensic examiners are still at the scene.
Det Ch Insp Jon Williams, who is leading the investigation, said: "I have a team of approximately 25 detectives and staff working on the case.
"This is an extremely distressing incident. I would reiterate that we are not looking for anyone else in connection with the death at this time and there is no risk to the wider community.
"However, I would urge anyone with information about this incident to contact police - it could be crucial in assisting us with this investigation."
Monmouthshire councillor for Abergavenny Jane Foulser said she was "absolutely devastated".
She said everybody she had spoken to was very upset about what had happened.
"It's a very good and close community," she said.
"I've lived in Abergavenny all my life. People are genuinely kind. I think the difficulty is around areas like this."
Anyone with any information about the incident should contact Gwent Police on 01633 838111 or Crimestoppers on 0800 555 111.