A man was being questioned today after a woman was found dead and a child left critically injured.
Police discovered the body of the 30-year-old victim at a house in Flint, north Wales, following reports of a disturbance at 1.30am yesterday.
The child - understood to be a 12-year-old boy - was rushed to hospital from the scene in the cul-de-sac at Cae Hir.
He remained in a critical but stable condition at Liverpool's Alder Hey Hospital.
Neighbours said a Polish family and a lodger, also a Polish national, had moved into the house just before Christmas.
It is believed a man ran out of the house into the street shortly before the emergency services were called and shouted for help.
A North Wales Police spokeswoman said: "House-to-house inquiries are being conducted in the area and police are keen to speak to anyone who may have been in the Cae Hir area between 12.30am and 1.30am (yesterday)."
A woman neighbour, who lives doors away from the murder scene, said: "I didn't see or hear anything until I was awoken by a load of commotion and looked out of my bedroom window to see lots of police cars.
"You do not expect anything like that to happen around here.
"I've been told that a man came out of the house and shouted, 'Help, help' before someone called 999."
She added: "I did not know the woman involved but I knew her son because he calls round to see my boy and play out.
"I hope he pulls through, it's terrible."
Anyone with information about the incident should contact Mold CID on 101 or 0845 6071001 (Welsh line), 0845 6071002 (English line) or Crimestoppers Wales on 0800 555111.