A man has been arrested on suspicion of murder after a woman was killed and two others suffered serious stab wounds.
The 40-year-old was detained overnight after officers were alerted to attacks at two separate south London flats on Monday evening.
A woman aged 28 and a 17-year-old girl were found with knife wounds at 7.10pm at an address in Tilson Gardens, Brixton.
The woman was pronounced dead at the scene, while the teenager was taken to a south London hospital and is in a serious but stable condition, Scotland Yard said.
Half an hour earlier, another woman, aged 46, was found at a property in Redlands Way with a number of injuries, including stab wounds. Her condition is described as critical.
Forensic examinations were taking place at the two properties, which lie less than a mile apart.
Police said all three victims were known to the man being held in custody at a south London police station.
A woman who lives in Redlands Way said she came outside when she heard a woman screaming that someone was trying to kill her.
She said: "The woman had got out on to the balcony and she was just screaming. There was this tall, black guy who came out of nowhere - it was like a film.
"He just grabbed her and stabbed her in her back - a couple of us saw it. The children were playing out in the park right in front which made it more traumatic.
"People started calling the police and I was trying to get my daughter inside so I could go down to see whether I could do anything.
"The guy escaped but we saw her coming down with bandages and the bandages were bleeding."
It is understood an eight-year-old boy was in the bathroom of the Tilson Gardens property when the attack happened.
The suspect was arrested on a bus in Leigham Court Road, Streatham, south London, shortly before 1am.
