Police are investigating if an 11-year-old boy found dead with cuts to his head was attacked by the family dog.
A man is being questioned by police after the child died at a house in the Queens Avenue area of Newtownabbey, County Antrim, at midday on Saturday.
It is understood a dog was in the house at the time.
One line of inquiry is that the boy had been attacked by the animal.
No official cause of death has been confirmed by the authorities and a post-mortem examination is to be carried out.
Paramedics were called to the boy's home on Sunday.
The Northern Ireland Ambulance Service said the boy had "lacerations to the head" and was taken to the Royal Hospital for Sick Children.
The PSNI said it was investigating the death.
Forensic officers were at the house for several hours on Sunday.
Newtownabbey SDLP councillor Noreen McClelland, who was at the scene, said distraught neighbours had watched as the child was taken out of the house by paramedics on a stretcher.
"They said there was a lot of blood. It is just horrible, a terrible tragedy.
"How do you deal with something like that.
"Everyone is really upset.
"We don't know yet what has happened," added Mrs McClelland.