Residents in east London near a property where two men died have told how they were awoken by screams.
A 28-year-old woman was arrested after the incident in Ilford on Sunday morning.
The men were found seriously injured at the property in Tavistock Gardens and died at the scene, the Metropolitan Police said.
The woman, who had non life-threatening injuries, was detained at the scene and taken to hospital for treatment.
Police have set up a wide cordon around the area and several forensics officers have been seen outside the house.
A man who lives a short way down the street told the PA news agency he woke to the sounds of a woman screaming.
Kuddus Miah said: “She was screaming ‘Help, help, call the police’.
“The police and ambulances were there very quick.”
The 44-year-old said a neighbour told him they saw a woman who was “coming in and out of the house, crying out for help, and apparently had a knife in her hand”.
Mr Miah said he thought those involved in the incident were new tenants, adding: “We’ve lived here around 15 years and it’s a very quiet neighbourhood, it’s shocking.”
Another man, who gave his name only as Singh, described how a woman he saw was “quite hysterical, calling for the police, screaming”.
He added: “She was at the doorstep then went back inside and then out again, screaming and screaming for help.”
A Taser was deployed during the arrest, the Met said.
Officers were called to the property shortly before 4.30am to a reported disturbance.
Police, medics and ambulance staff attended but, despite their attentions, the men died at the scene.
Homicide detectives in Scotland Yard’s Specialist Crime Command have been informed and a crime scene is in place.
The men’s next of kin have not yet been informed.
Neighbour Inamul Hussain, 32, told reporters he called police after hearing a woman screaming.
He said: “I saw them Taser her, she had blood on her. I heard police say ‘put the knife down’.
“She was screaming something about her husband but it was quite broken, I think they’re Polish.
“Several men and several woman live there, they are always partying and drinking.”
Mr Hussain took a video of several police outside the house, during which officers can be heard shouting “show me your hands now” and “come here now” and “get out, get on the floor now”.