A man has been arrested after a fatal stabbing in west London, the Metropolitan Police said.
Officers were called to Albany Parade, Brentford, at around 7.50pm on Friday and found a man, believed to be aged 20, dead at the scene.
An 82-year-old woman was also found with stab wounds and was taken to hospital. Her condition is described as serious but not life-threatening.
The force said a man aged in his 30s was arrested on suspicion of murder and attempted murder on Saturday morning and he remains in custody at a London police station.
Police said there is no evidence linking the stabbings to terrorism and no-one else is being sought over the incident.
Inquiries are ongoing to establish if anyone involved was known to each other.
The grandson of the 82-year-old left flowers at the scene on Saturday morning.
He walked up to the police cordon and put down a bouquet, then left the scene. He refused to speak to reporters.
Officers believe they know the identity of the man killed and are providing support to his family, the Met said.
An urgent investigation is being led by homicide detectives from Specialist Crime.
Detective Chief Inspector Brain Howie said: “A number of cordons remain in place in and around Albany Parade, Albany Road and the surrounding area. Any local people who have information or concerns should speak with officers working at these location.
“I would like to hear from anyone who witnessed the incident or had any interaction with the suspect near the scene but has yet to speak with police. Also, anyone who may have footage, whether from doorbells, dashcams or mobile devices, is also urged to check that material and make contact with police should there by anything relevant to our investigation.”
Anyone with any information has been asked to call 101, quoting the reference number 6423 of November 12.