A man has been arrested on suspicion of murder after a woman and a five-year-old boy were found stabbed to death in north London.
The victims are believed to be mother and son and were known to the arrested man, Metropolitan Police said.
Officers were called to a home in Brookside South, Barnet, at 1.37pm today. Paramedics and the Air Ambulance were also deployed.
They found the woman, 37, and the boy with stab wounds and they were pronounced dead at the scene.
A man, also 37, has been arrested and the Met's Specialist Crime Command is investigating.
Chief Superintendent Sara Leach described it as "an incredibly challenging scene" for the first responders.
"Specialist detectives are working to establish what took place and a man is in custody," she said.
"While they are keeping an open mind as to what has taken place, I would like to reassure residents in the local area that there is nothing to indicate, at this stage, that anyone else was involved in this incident.
"I would urge anyone who saw or heard anything unusual earlier today, or in recent days, to come forward and speak to the police. Your information could be vital as the investigation moves forward."
Initially, the Met Police said a woman and five-year-old girl were victims of the attack.
It has since corrected this, saying the child killed was a boy.
Information can be provided by calling 101 with reference 3590/21JUN.
Alternatively, people can contact Crimestoppers anonymously on 0800 555 111.