UPDATED: Police are investigating the death of 20 year old Muktar Ali who lived in Borough Road SE1 and are appealing for witnesses.
At about 1am on Sunday 26 August an ambulance crew was called to a disturbance in Princes Square W2.
They found the victim with a cut on the back of his head but he refused to make any allegations and said he had fallen over.
He was taken by ambulance to St Mary's Hospital in Paddington where he discharged himself the same day to return to his home in Borough Road SE1.
The following day, Monday 27 August, he attended another London hospital where he was initially diagnosed with a whiplash injury.
He returned home but then suffered a seizure. He then returned to the hospital where he was found to have a brain injury.
He was then transferred to the National Neurological Hospital in Holborn where he died on Friday morning.
A post mortem held at Westminster Mortuary has established cause of death as a fractured skull.
On Sunday morning a male in his early twenties was arrested in the NW8 area on suspicion of murder. He is in custody at a London police station.
The Met's Homicide Command under DCI Tony Nash is now investigating the death.
Anyone who witnessed the incident or can assist police in any way with this inquiry should contact the incident room at Hendon on 020 8358 0100.