One arrest has already been made after Ruislip resident Osman Shidane, 20, was stabbed to death. He died on Friday after being attacked last Tuesday.
An urgent appeal has been launched with the aim of finding witnesses as police look for further clues on what occurred.
Police were called shortly after 9pm on Tuesday, 15 May to “reports of a man suffering from stab injuries on Victoria Road”.
The London Ambulance Service and London's Air Ambulance also attended.
Mr Shidane was taken to a central London hospital in a critical condition. He died at 5.16pm on Friday, 18 May.
His next of kin have been informed.
A post-mortem examination held on Saturday, 19 May gave cause of death as multiple stab wounds.
Detective Chief Inspector Paul Healy, said: “This was a violent attack in which Osman was stabbed several times. I would urge anyone who was in the area of Victoria Road on 15 May between 8.30 PM and 9.30PM and who is yet to speak with officers to come forward and contact the incident room.”
An incident room has been opened by detectives from the Homicide and Major Crime Command. Enquiries continue.
Anyone with information is asked to contact the incident room on 0208 358 0200 or Crimestoppers anonymously on 0800 555 111.
- A 16-year-old boy was charged with murder on Saturday, 19 May.
- A 15-year-old girl who was arrested on Wednesday, 16 May on suspicion of assisting an offender has been released on police bail.