Police inquiries have established Mr Wharawhara's friend first approached staff in the Auckland Hospital emergency department just over two hours after the alleged attack, at about 10.06pm.
READ MORE: Men had to carry friend to hospital
"Our information is that the friend was concerned about Mr Wharawhara's condition and sought some medical assistance," Detective Inspector Kevin Hooper said.
"Hospital staff called ambulance services at about 10.15pm and that call prompted an ambulance communications call taker to contact police to advise that a person in a park was unconscious after being assaulted.
"The caller further advised police that an ambulance could not be dispatched because there was no specific location for it to go to."
Police said a suggestion was made that officers attend at the hospital to accompany the man to wherever his friend was.
"The deceased's friend had been asked to wait at the hospital so that emergency services could accompany him to where his friend was but police were advised that he'd apparently left the area before exact details of Mr Wharawhara's location could be obtained," said Mr Hooper.
By 10.42pm further information had been received from a different informant suggesting there was a body in a park. Officers immediately went to the scene and an ambulance was requested.
"Officers did not find any assault victim or deceased at Outhwaite Park because, as it later transpired, he was in the process of being taken to hospital by two associates," Mr Hooper said.
"Police were notified shortly after 11pm that Mr Wharawhara was at Auckland Hospital so advised ambulance staff to stand down at 11.12pm.
"The investigation into the circumstances of Mr Wharawhara's death continues and police cannot rule out the possibility of further charges being laid in relation to it."