The 21-year-old was found with multiple wounds after a “truly shocking” attack in church gardens, South Ealing on Tuesday around 12.10.
Police were called in on reports of a stab wound in Roberts Alley, near Grange Elementary School.
The officers arrived along with paramedics and a London aviation ambulance.
Scotland Yard stated that the victim had a number of stab wounds, and despite all the efforts of emergency services, she was found dead at the scene.
Law enforcement officers are sure that they know the identity of the woman and inform her close relatives.
A post-mortem examination will be organized in due course. A crime the scene remains in place while forensic experts seek clues.
Chief Superintendent Sean Wilson, commander of the West Zone Metro, said: “This is a truly shocking incident that will, of course, cause serious concern to the local community and the people of London in general.
“Violence of all kinds, but especially against women and girls, has a profound impact on the community, and it will certainly affect the confidence of the people in the area who are engaged in their daily affairs.
“I want to assure the Ealing community that a team of specialized homicide detectives has launched an investigation and they will use their skills and experience to ensure that the perpetrator is brought to justice.”
The woman, whose home is at the crime scene, said she heard “a bunch of screams” at night.
She added: “It’s such a shame. How awful. “
Liberal Democrat adviser John Ball tweeted: “It is very sad to hear this morning about the murder that took place last night in Roberts Alley, South Ealing. Such a tragedy.
“Grange School, Grange Nursery and Grange Preschool are on police cordon, so closed today.”
Teachers posted on the Grange School website: “Urgently – the school is closed today due to a serious incident.”
Anyone with information is asked to call the police on 101, with reference to CAD 77/17 May, or anonymous Crimestoppers on 0800 555 111.