The fatal stabbing of a woman near a bus stop in north-west London was an "isolated incident" and no further suspects are being sought, police say.
The victim, aged 66, was treated by paramedics on Burnt Oak Broadway in Edgware on Thursday but died shortly before midday.
A 22-year-old man remains in police custody in north London after being arrested on suspicion of murder in Colindale, the Met Police says.
The woman's family has been informed.
Emergency services were alerted to reports of a stabbing by the junction of Limesdale Gardens at about 11:50 BST.
Det Ch Insp Alex Gammampila said: "I know that the effects of this incident will be felt throughout the local community and would like to reassure everyone that a man is in custody and we are not looking for any other suspects.
"We are working hard to establish the full circumstances and motive for this offence, which we believe to be an isolated incident."
Supt Tony Bellis said: "A family has been left devastated by this shocking attack and my thoughts are with them at this unimaginably difficult time."