EIGHT people were arrested on suspicion of murder after two teenagers died from suspected stab wounds.
The boys were found seriously injured in Brentwood, Essex, and later pronounced dead at the scene.
Five of those arrested have since been released, with two from Grays, aged 19 and 20, and a 21-year-old from South Ockendon remaining in custody.
Four people – a 20 year-old man from South Ockendon, and three men from Grays aged 19, 20, and 49 – have been told they face no further action.
A 40 year-old man from Brentwood has been released under investigation.
A third victim was treated for injuries which police say aren't life-threatening or life-changing.
It's understood the boys suffered suspected stab wounds, the BBC reports.
One horrified neighbour heard screams and someone "yelling out in pain" with officers and paramedics scrambled to Regency Court about 1.30am.
Police have launched a double murder investigation into what they described as "probably a targeted attack".
'SCREAMS'
Detectives later said there was an altercation between "two groups" who "knew each other".
Local resident Mark MacIntosh said: "I came home last night, I came in five minutes before I heard the shouts and screams.
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"I said should I go down as I usually do if I think there's something serious but I couldn't hear."
He added: "And now as I reflect I realise that what I heard was somebody yelling out in pain who may have lost his life shortly thereafter."
Mr MacIntosh said he had warned police three weeks ago to beef up patrols amid reports of anti-social behaviour
He added: "There's constant anti-social behaviour, drinking, drugs, shouting, fighting.
"I've heard people saying ''I'm going to kill him'' up there.
I came home last night, I came in five minutes before I heard the shouts and screams.
Local resident
"I've come down and broken up a knife fight down at the bottom here before."
Another resident told Essex Live: "You feel for the family - some poor mother has had her world destroyed.
"We have always had noise and what-not from the clubs and kids coming up and down but I wouldn't expect this."
Family and friends of the victims laid flowers at the scene with many teenage mourners among those paying tribute to the two boys who were killed.
'SHOCK'
Detectives are working to establish exactly how they died, and a forensic post-mortem examination will be carried out.
Essex Police Detective Chief Inspector Mark Barber said the horrifying incident was "probably a targeted attack" and was an isolated incident.
Detective Chief Inspector Andy Clarkson, of the Kent and Essex Serious Crime Directorate, led the investigation through the night.
He said: "This incident has required an immediate and a large-scale response and officers and investigators have worked through the night to piece together what happened in the lead up to this tragic incident.
“Our investigations will continue throughout today.
“We understand there will naturally be shock and concern within the community after such a tragic loss of life. But, at this stage, we do not believe there is any wider threat to the public."
Chief Inspector Mark Barber added: “There will continue to be a highly visible police presence in Brentwood this morning and indeed throughout the day.
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“I am acutely aware that this incident will shock many without the community."
Cops are urging anyone who was close to Regency Court or the roads around it in central Brentwood at the time, or who has any information at all, to come forward citing incident 125 of October 24.