
A woman has died from stab wounds following an armed siege at a house.
Police said the woman in her 40s died at the scene of the stand-off in Cromwell Road, Peterborough, at about 06:40 BST.
A woman in her 30s, and a nine-year-old boy were taken to hospital, but police said their injuries were not thought to be life-threatening.
A man in his 40s has been arrested on suspicion of murder and taken to hospital with minor injuries.
Cambridgeshire Police sent armed officers who negotiated with a man inside the property before arresting him.
Earlier in the morning, a neighbour said she had seen a boy, aged "about nine" running in the street with blood on him.
A police spokesman said all three victims sustained stab wounds and all four involved were believed to be related.
Cambridgeshire Police said it was not looking for anyone else in connection with the incident.
Specially-trained officers were liaising with the victims and their families, a spokesman said.