Ms Allena was found with "serious head injuries" in Cranbrook Road at around 2.45am, and later died in hospital.

Speaking at a news conference this afternoon, Met Police Chief Superintendent Stuart Bell said she was the victim of an "opportunist stranger attack".

He said Ms Allena, who was local to the area, "suffered multiple serious injuries that contributed to her death", but there is "no evidence at this time that weapons were used during the attack".

Detectives had previously warned women in the area to be "alert" while the person responsible is still at large.

"Since the attack, officers have worked every hour to determine more about the circumstances - we are determined to catch the person responsible," he said.

Describing the events of Sunday night, CSI Bell said: "I want to briefly summarise what we know at this stage at 2.44am on Sunday, 26 June Met officers were called by London Ambulance Service colleagues to a seriously injured woman found by members of the public in Cranbrook Road in Ilford.

"Despite the best efforts of paramedics and doctors at hospital, she died later on Sunday morning.

"Zara who lives locally was walking along Cranbrook Road in the direction of Gants Hill Station when she was assaulted, which is now believed that she was a victim of an opportunist stranger attack."

He added that the victim's family is "up to date with our progress" and are being supported by specialist officers.

A post-mortem examination is yet to take place, but a full forensic probe of the scene has been completed.

House-to-house enquiries are also being carried out.

Detectives particularly want to hear from anyone in or near Cranbrook Road between 2am and 3am on Sunday, including anyone who drove through or may have captured the scene on a dash cam.

Any suspicious behaviour in Ilford that night should also be reported to police on 0208 345 3715.