Police says five "random stabbings" in north London could be linked as they investigate "just one individual perpetrator".
It follows the stabbing of a man by an attacker matching the description of a knifeman who injured four people in one night in the area. The culprit in all five stabbings is thought to be a tall, skinny black male wearing a hooded top.
The latest victim, aged in his 30s, was left with life-threatening injuries when he was stabbed in Aberdeen Road, Enfield, north London at about 5am on Tuesday.
Despite previously not linking the stabbings, police said early Tuesday evening: "The actions of the suspect, the fact they are in a similar area, and the descriptions given, mean that we are potentially looking at just one individual perpetrator."
A man in his 30s was arrested earlier in the day in connection with the attack on Tuesday morning.
Two men previously arrested on suspicion of causing grievous bodily harm remain in custody, investigators have until later on Tuesday to interview them.
The Met said it is too earlier to comment on the progress of the investigation.
Chief superintendent Helen Millichap earlier said: "My message to the public, here in Edmonton, is that the police are here, the police are out and about to make you safe.
"We have made arrests in relation to this investigation but as I mentioned before, until we can unequivocally say that these are linked and that we know that we have our suspect in custody , I do want the public to remain alert.
"I do want the public to report anything suspicious to us but I do also want them to feel as safe as they can. We are not advising people to stay indoors, the police are here and the police are around."
The stabbings have left two critically hurt and one with potentially life-changing injuries.
At the weekend, a 45-year-old woman was the first victim when she was stabbed once in her back at about 7pm on Saturday in Aberdeen Road, and left in a critical condition.
Then at 12.15am on Sunday, police were called to Park Avenue where a 52-year-old man had also been injured with a knife. He has since been discharged from hospital.
The third attack was on a 23-year-old man just before 4am near Seven Sisters Tube station. He is in a critical but stable condition.
The final attack occurred at about 9.40am on Sunday in Brettenham Road where officers found a 29-year-old man with a stab injury to the back.
His injuries are life-changing.
Residents told of their fear following the latest stabbing.
Kelvin Ojo, 36, said: "It's scary now, this is not normal. They can't find this person, it's just one guy.
"It's been peaceful for a while until all this drama started coming up. Now I'm starting thinking about moving from this area, I'm not liking it.
"It could happen to anyone - my friends, my family, it could happen to me. It's really scary."
And, Mike Kalongi, 28, who lives near the scene of the latest stabbing, said: "It's getting a bit close.
"It's a bit scary. I usually go to the gym at night, but over the last few days I decided not to.
"I'm going shopping. I usually have my headphones on but I want to stay aware and try not to be a victim."
A security guard said he saw officers running to arrest the man, who "just stopped".
"There were more than 15 police," he said.
"They were searching him, pulling things out of his pockets, putting things in the (evidence bag).
"I didn't see a knife inside there."
He said the man was a "skinny black geezer", adding: "He wasn't talking."