An inquest has heard that a psychologist from Cardiff Bay could not have survived a traumatic brain injury after he was allegedly attacked.
Dr Gary Jenkins died in hospital 16 days after suffering critical injuries in Bute Park. Two men and a teenage girl have been charged with murder.
A post-mortem on the 54 year-old concluded the cause of death was a 'blunt head injury'.
Pontypridd Coroners Court heard Dr Jenkins was given full intensive care treatment at the University Hospital of Wales in Heath, where he worked for mental health services.
The father-of-two was given a ''right sided craniotomy and decompression'', but his condition deteriorated, and he passed away after being transferred to palliative care.
The hearing was adjourned by Rachel Knight, assistant coroner for South Wales Central, until next May, once a criminal trial has taken place.
Jason Edwards (25), from Riverside, Lee Strickland (36), of no fixed abode, and a 16 year-old girl who can't be named for legal reasons, are due to go on trial in January, accused of murder.
They are due to reappear at Newport Crown Court for a plea hearing in October.