Forensic results could hold the key to finding those responsible for two brutal attacks during a night of chaos in Merivale.
A teenage girl was sexually assaulted on the grounds of Merivale School about midnight on Saturday. Less than an hour later a 20-year-old man was stabbed during a fight on Mansels Rd.
Detective Sergeant Iain Chapman said police had no leads on the sexual assault, but were still investigating.
The girl was attacked by a complete stranger on the school grounds near Henderson Cres, Mr Chapman said.
The stabbing happened nearby on the corner of Mansels and Alverstoke Roads, about 12.50am on Sunday.
A 20-year-old man suffered a three centimetre deep stab wound to his armpit during a fight between five people, Mr Chapman said.
He was taken to hospital but has since been discharged.
"A fight has occurred between two opposing sides unknown to each other. Alcohol was involved. On one side one of the guys has had a knife and the other guy has had a tomahawk or hatchet," he said.
"Both sides were actually fighting and then someone's brought a knife to a fist fight. It could have been a lot worse. It was only through luck that we weren't dealing with worse. It could have been a homicide."
The offenders had left before police arrived and no arrests have been made.
Mr Chapman said the attacks occurred on a chaotic night in the suburb.
"I understand there was a large amount of disorder in Merivale. There was at least one large party," he said.
"We know the victim had been at the party earlier in the night but we have no reason to believe the other group was."
Mr Chapman said police were waiting on forensic results from items collected at both sites.