The group who left a teenager critically injured at the Otara Town Centre was seen chasing two other young men with a metal baseball bat just before the beating.
After speaking to witnesses police now believe the 17-year-old was an innocent victim who was simply in the wrong place whenhe was attacked by the group and left for dead.
He is expected to succumb to his injuries in the next two or three days.
Last night the boy's family, including the aunt he lived with in Otahuhu, were at the hospital with him.
The aunt told police she thought he was out with a friend on Saturday night but he appears to have been alone at the time of the attack.
Detective Senior Sergeant Dave Pizzini said the teen was found unconscious and lying in a pool of blood by a security guard, just before midnight on Saturday. The guard had been driving along East Tamaki Rd just minutes earlier when he saw a group of four young men run across the road.
One of them was carrying a baseball bat and they were chasing two other young men.
Suspicious of what the four men were up to, the guard parked his car and went to investigate.
In that time the men ran at the teen, who was walking towards them, and attacked him.
Mr Pizzini said it was not clear how many of the group were involved in the attack.
It was also not known if the four men thought the teen was one of the two people they had been chasing or just came across him and attacked anyway.
Police have yet to identify the attacking group and Mr Pizzini said it was too early to say if they were members of a gang.
The man seen holding the bat is described as being of dark complexion, in his early 20s, of slim build and about 6ft (1.82m) tall.
He was wearing black jeans and a white T-shirt.
Police want to speak to people who were in the area, especially people at the nearby Galaxy nightclub. Phone 295 0200 and ask for Operation Galaxy staff.
