A manuhunt is under way after a mother an daughter were found stabbed to death in their home.
The victims aged 33 and 66 were found dead in a property in in Golders Green Crescent, north west London.
Scotland Yard said they are are looking for 27-year-old Joshua Cohen in connection with the killings.
Police said Cohen, who is described as a white male, 5ft 9ins tall with short cropped hair and stubble, has mental health issues and should not be approached.
He was last seen wearing a red Nike hooded sweatshirt with a white logo on the chest. He was also wearing white trainers and dark grey trousers or tracksuit bottoms. He has recently shaved off his hair and eyebrows.
A Scotland Yard spokesman said : "He has mental health issues including paranoid schizophrenia and should not be approached by members of the public.
Any sightings of Joshua Cohen should be reported to police immediately via 999."
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.