An 11-month-old baby girl found stabbed to death in a flat has been named by police as Harley Ruck.
The mother of the child, named locally as Jade Ruck, 22, is believed to be the woman arrested on suspicion of her murder.
The devastated family of the child described the killing as a "horrific tragedy" in a brief tribute.
Police were called to a flat in St Davids Road, Abergavenny, south Wales, at 5.30am on Saturday. Harley was discovered inside and, despite efforts to revive her, she was pronounced dead soon afterwards.
A 22-year-old woman was arrested on suspicion of murder. Gwent Police said she has since been detained under the Mental Health Act and is undergoing medical assessment.
Officers also revealed that a post-mortem had established that Harley died of multiple stab wounds.
The family statement said: "In the event of a horrific tragedy to our beautiful, happy, loving little daughter, granddaughter, (great granddaughter) niece and cousin who was loved dearly and will be sadly missed by all around her, especially by her lost heartbroken mum."