A man ran across back gardens and was cornered by police in a house after a woman was beheaded with a machete.
Police were called to reports of a man armed with a knife in Nightingale Road, Edmonton, at 1.07pm and a woman was found dead in a back garden.
A 25-year-old man was arrested and officers are not looking for anyone else in connection with the incident.
According to the Metropolitan Police, a man was seen attacking “a cat or a dog” before he was eventually arrested by police.
Speaking at a press conference just after 5.30pm, commander Simon Letchford said officers had to smash windows in houses in order to detain the man.
However, he did not confirm whether the attacker knew his victim and the circumstances surrounding the attack.
He said: “These sort of events on our streets are very unusual and not common.
It was a fast moving and difficult situation and police did everything they could to make people safe.
“They evacuated houses and put their lives on the lines to make sure more people didn’t get harmed. I praise them.”
Officers are now undertaking door-to-door enquiries to find out more about what happened.
The Independent Complaints Police Commission has also been notified.
Although the victim’s family has been traced, police have not yet released her name.
Commander Letchworth added: “We still need to understand the motivation behind this attack and before we’ve done that we aren’t willing to speculate as to what it might be.
“Based on what we currently know we don’t believe it to be terror related.”