Detectives launched a murder inquiry today after a woman was found mutilated and dying in the street.
The 28-year-old was discovered by a passer-by in Greenford, north west London, at about 7pm last night.
Witnesses said she had serious head injuries and one of her hands had been cut off.
Police and paramedics were called and she was taken to Charing Cross Hospital where she died about four hours later.
Investigators believe the woman may have been targeted after an acrimonious split with a former partner.
They were preparing to question six men held at several west London police stations after they were arrested earlier today.
One line of inquiry is that the woman was attacked elsewhere and dumped on the pavement, in Braund Avenue at its junction with Verulam Road.
Detective Chief Inspector Andy Chalmers, who is leading the inquiry, appealed for help from the public.
He said: "When the victim was found we know that a lot of people were in the street and that several people may have tried to administer first aid before the police or ambulance arrived.
"These people left the scene before speaking to police and I would ask that anyone who was there, or anyone else who has information about the incident, call us in the strictest of confidence."
A Metropolitan Police spokesman added: "Officers believe they know the woman's identity and have informed next of kin, however, we await formal identification.
"A post mortem examination will take place later today. Officers from the Homicide and Serious Crime Command at Hendon are investigating."
* Anyone with information should call the incident room on 020 8358 0200 or Crimestoppers on 0800 555 111.Reuse content