Edmonton stabbings: Police tell residents to remain vigilant
Residents in north London where four people were "randomly" stabbed within 10 hours have been told to be vigilant despite two arrests being made.
Two people are still in a critical condition in hospital following the attacks in Edmonton over the weekend.
Det Supt Luke Marks said people should "remain vigilant, especially when walking alone".
A nearby grammar school was put a "lock-down procedure" in place as a "precautionary" measure.
In an email to parents, head teacher of the Latymer School Maureen Cobbett said students would not be allowed to leave the school during breaks and lunchtime, and after-school activities would not take place "until further notice".
Police believe the four people attacked, who were all stabbed in the back, had been selected randomly.
The first victim, a 45-year-old woman, remains in a critical condition after she was attacked in Aberdeen Road at 19:02 GMT on Saturday.
Four hours later, a 52-year-old man was stabbed half a mile away in Park Avenue. He has since been discharged from hospital.
The next victim, a 23-year-old man, is in a critical condition after being attacked near Seven Sisters Tube station at about 04:00 BST on Sunday.
The final stabbing happened at 09:42 in Brettenham Road where a 29-year-old man was attacked. He is receiving medical treatment but his injuries are not life-threatening.
Two men are in custody after being arrested on suspicion of causing grievous bodily harm.
Police have been given extra time to question them.
One was held in Fore Street, Edmonton, on Sunday morning while a man aged in his 40s was arrested at a residential address at about 19:00.
Det Supt Marks said police still "believe that a single suspect was involved" and inquiries were ongoing, although the attacks were not thought to be terror-related.
The suspect has been described as a slim black man, who is about 6ft 3in tall and was wearing dark clothing.
The Met previously said they thought "mental health issues may be a factor" and extra police patrols had been put in place "to keep the public safe and catch the individual responsible".