A murder investigation is under way following the death of a 10-year-old boy in Acton, west London.
A woman in her 40s has been arrested on suspicion of murder, police said.
She walked into a police station in the early hours of Sunday to speak to officers.
A short while later, the boy was found dead at a home in Cumberland Park, Acton.
Scotland Yard said police believe they know the identity of the child, who was known to the woman.