A manhunt is underway in London after four people were stabbed in what's believed to be a linked series of random stabbings.
The incidents happened in the Edmonton area over a more than 12-hour period on Saturday night and Sunday morning.
One woman and three men were all separately stabbed in the back - with the 45-year-old woman and a 23-year-old man said to be in a critical condition.
Another of the men is said to have sustained injuries that are "not life threatening but potentially life-changing".
Police say extra resources have been called upon to search for a male suspect.
Met Police's Stuart Smillie said: “Police are treating the four stabbing related incidents as potentially linked.
"The four victims are all from different backgrounds and appear to have been selected at random due to them being alone and vulnerable. There is nothing to suggest this incident is terror related."
He added: “We are working on the hypothesis that the single male suspect is acting alone and mental health issues may be a factor.
"All of the people he has targeted have been walking alone and he has approached from behind without warning."
Members of the public in the area are being urged to remain vigilant.