Police developed concerns for the welfare of a man at a flat on Norman Crescent on Sunday (October 19) after receiving multiple calls.
Officers attended with paramedics and a 19-year-old man was pronounced dead at the scene.
A woman aged in her 50s, from Brentwood, was arrested on suspicion of murder and remains in custody for questioning.
Detective Inspector James Holmes, who is leading the investigation, said: “Our enquiries are at an early stage and I’d first like to emphasise that this is an extremely sensitive and distressing matter.
“We are supporting the distraught family of a teenage man who has lost his life in tragic circumstances and our first thoughts are with them as we work to understand what happened.
“As tempting as it might be for the public to speculate about the circumstances, I would please call for this to be avoided, keeping in mind the trauma suffered by the family.
“We will issue updates on our investigation as soon as we are able and there will be a time and a place for the full facts of this matter to be heard.
“We remain at the scene in Brentwood. This is an isolated incident, confined to a single address, with no threat to the wider community.”
The family of the victim are aware and are being supported by Essex Police officers.
