death of 21-year-old student Roberto Laudisio Curti but added that it was "impossible to believe that he would have died but for the actions of police".
All of her recommendations were accepted by police, including that five officers involved be referred to an independent watchdog and there be an immediate review of the criteria for use of Taser stun guns.
But Police Commissioner Andrew Scipione, who admitted the coroner's report was "quite scathing", said Tasers would continue to be used.
"These weapons save lives," he said.
Officers pursued a shirtless Curti, who had become paranoid and was acting erratically after sharing an LSD tab with two friends, in the mistaken belief that he had committed an armed robbery on a Sydney convenience store.
In shocking him at least 14 times, tackling him to the ground and blasting him with pepper spray, the actions of a number of police officers were "reckless, careless, dangerous, and excessively forceful", Jerram said.
"They were an abuse of police powers, in some instances even thuggish."
She said one probationary constable used his stun gun in a "wild and uncontrolled" manner on the Brazilian, who issued terrible screams and groans as half a tonne of police piled on top of him as he lay on a city street.
"A few of the other constables seem to have thrown themselves into a melee with an ungoverned pack mentality, like the schoolboys in 'Lord of the Flies'," she said, referring to the novel and film about boys who turn savage after being stranded on an island.
Jerram said many of the police had "no idea what the problem was, or what threat or crime was supposedly to be averted, or concern for the value of life".
Police said Curti had shown a "superhuman" strength as he struggled against them, but the coroner said evidence from cameras on the Tasers showed he was quickly handcuffed after being thrown to the ground.
She said one officer lay across his back, another knelt on him and others held his arms and legs as he was then repeatedly Tasered by two officers while another sprayed pepper spray in his face.
Minutes later he was seen to be unresponsive and could not be revived.
Curti's family members welcomed the findings but said they would still be pushing for those responsible to be held accountable.
"Whilst nothing will ever bring Beto back, we continue to push for those responsible to face the consequences of their appalling behaviour on that night," family spokesman Michael Reynolds told journalists.
Watch YouTube video here. The video contains disturbing footage