An 11-year-old girl named by police as Jasmine Forrester has died in hospital after being stabbed at a house in Wolverhampton.
A man has been arrested on suspicion of attempted murder following the incident at a house in Kent Road on Friday.
Officers were called shortly before 1am after a neighbour heard a disturbance and found the girl with multiple injuries, including one to the head.
The 51-year-old suspect, who is related to the girl, is also in hospital receiving treatment for a cut hand.
A woman in her 80s suffered a suspected dislocated shoulder during the incident.
Superintendent Harvi Khatkar said: This is an extremely distressing incident and our sympathies go out to everyone affected.
We are working to establish exactly what has happened, and fully understand the impact that this will have on the community.
But we do believe this is an isolated incident, and we are not looking for anyone else.
Extra officers will be out patrolling the area to offer reassurance to residents.
The house has been cordoned off to allow forensic experts to conduct an examination.