A man with knife allegedly killed one woman and injured two others in a stabbing rampage with children metres away.
A 40-year-old was arrested on suspicion of murder after the horrifying attacks at two flats in Brixton, south London, yesterday.
A 46-year-old woman was stabbed multiple times at a flat in Redlands Way and is in hospital in a critical condition.
About half an hour later, police were called to Tilson Gardens, where another two women had been attacked - a 28-year-old, who was pronounced dead at the scene, and a 17-year-old who is in a serious condition.
An eyewitness who lives in Redlands Way said she came outside when she heard a woman screaming that someone was trying to kill her.
She said: “I came out when I heard her scream that someone was killing her and shouting for help. 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.”
She said she understood that a young girl was in the flat at the time.
Police were called to Redlands Way at around 6.40pm, along with paramedics and the air ambulance.
Half an hour later they were alerted by ambulance crews who were treating the two other women in Tilson Gardens.
It is understood that an eight-year-old boy was in the bathroom of the property in Tilson Gardens when the attack took place.
Forensic examination officers were searching a first-floor flat in Pearce House today.
The suspected attacker was arrested shortly before 1am as he travelled on a bus in Leigham Court Road, just over a mile from where the women were stabbed.
Detectives are not seeking anyone else in connection with the investigation, and it is believed all three victims were known to him.
Detective Inspector Will Reynolds said: “Our investigation is at a very early stage. However, we are confident that there are no outstanding suspects.
“We believe that all three victims were known to the man who is currently in our custody. There is no suggestion that the victims were selected at random.”
Speaking at Brixton police station this afternoon, Mr Reynolds said the 17-year-old girl and the 28-year-old woman are sisters.
He said: "The lady who was fatally stabbed is the sister of the 17-year-old girl who tried to protect her."
The teenager suffered stab wounds to her head and hands.
Young children were present at the scene of both attacks, which involved "extreme violence", and officers are trying to establish whether they saw anything significant.
Mr Reynolds said the suspected attacker is known to the police, but would not give any more details.
The dead woman was named locally as Keisha.
A woman who lives in the housing block at Tilson Gardens heard a boy raise the alarm by screaming from a balcony.
Hawa Musse, 20, said the dead woman was the mother of the boy and the sister of the injured teenage girl.
"The boy came out on the balcony," she said.
"He was crying and screaming. I went down to help."
Ms Musse said she and another neighbour ran outside to assist.
"She called the police and took the boy away,' Ms Musse said.
"He was shaking. He only had one piece of cloth around him."
Ms Musse then saw the injured girl outside the flat.
"She was sitting on the floor. There was a lot of blood coming from her head.
"She was saying 'My sister is inside'.
"I think she was talking to the police," she said.
Ms Musse described how the other neighbour took the phone off the girl to give instructions to the police, while she told five or six children who were playing outside the property to go away.
"I thought the children cannot see this," she added.