A 27-year-old woman is in a critical but stable condition in hospital after sustaining a serious head injury.
The London Ambulance Service was called to the flat in Old Devonshire Road, Balham, just before 2am on Tuesday, where they found the woman bleeding.
The woman was taken to St George’s Hospital.
A police spokeswoman said investigations were continuing.
She said: “We are keeping an open mind as to how she obtained the injuries.”
Update
Police said a 26-year-old man was arrested on Wednesday in connection with the incident.
He has been released on bail until July 28.
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