A 24-year-old woman is in a critical condition after she was stabbed in the arm and neck in an attack in which a young child was also injured.
Detectives said the knife attack in Walthamstow, east London, yesterday afternoon was not random, but they have yet to find a clear motive.
The victim was stabbed at a residential address in Hatherley Road at around 3pm and was taken by ambulance to a hospital in east London.
A six-year-old child who was also at the home suffered a minor injury which did not need hospital treatment.
Detective Chief Inspector Philip Langworthy said: "We are investigating a serious assault on a young woman. The motive remains unclear at this stage but we do not believe this is a random attack.
"People living and working nearby may have seen something that could be of vital importance to investigators. I would urge anyone with information to contact Waltham Forest CID on 07785 530686, 101 or Crimestoppers anonymously on 0800 555 111."