A man has been arrested on suspicion of murder after a mother and daughter were stabbed to death.
Scotland Yard said Joshua Cohen, 27, was arrested in connection with the killings of the victims, aged 33 and 66.
A member of the public spotted the suspect in Golders Hill Park, north west London, after detectives launched a manhunt on Saturday.
Police were called to an address in Golders Green Crescent on Friday at 8.50pm after reports that two women had been seriously injured, pronouncing them dead at the scene.
The suspect, who was known to the two victims, was arrested shortly before 2pm and was taken to a north London police station, police said.
Detective Inspector Ian Lott from the Homicide and Major Crime Command said: "Following a recent media appeal a discerning member of the public alerted police to a real time sighting and officers moved quickly to detain and arrest the man wanted for questioning shortly before 14:00hrs.
"This was a devastating attack on two women in their homes. Our investigation is ongoing."
Formal identification and post mortem examinations have yet to take place but police are confident they know the identify of the victims.
Their next-of-kin have been informed.