Sydney - A review into a riot at an Australian detention centre in Papua New Guinea found on Monday that an Iranian man was "brutally beaten" to death by a Salvation Army worker, as it warned of a major task to rebuild trust.
The unrest at the Manus Island camp in February also left 69 people injured as tensions flared among inmates about their fate under Australia's hard-line asylum-seeker policies.
An independent review on behalf of the Australian government found no particular factor caused the violence at a camp that has been condemned as too harsh by the United Nations.
"It is not possible to isolate one factor which, if handled differently, may have resulted in less injuries and damage or to apportion blame for causing the incidents directly to one or more of the parties involved," it said.
But it added that tensions were fuelled by frustration and anxiety over a lack of information about resettlement policies, and by dismay among inmates at hearing they had no chance of living in Australia.
There was also antagonism between some in the camp and PNG nationals working there, with some asylum-seekers treating them "in a disrespectful and racist manner".
Manus Island houses one of two remote Pacific camps used by Canberra in its tough offshore detention policy. The other is on Nauru.
Under the policy, any asylum-seeker arriving by boat is transferred to the centres for processing and permanent resettlement.
The review said tensions had been building for days before the riot and 30 to 35 transferees escaped on 16 February. They were recaptured and one inmate had his throat slashed by a guard. He survived.
The following day a protest turned violent with PNG police entering the compound and opening fire, during which Iranian man Reza Barati suffered a severe brain injury after a brutal beating.
The review cited an eyewitness who said the beating was "led by an identified PNG national employed by The Salvation Army and he named several other witnesses who he says can corroborate his statement".
The review recommended authorities speed up procedures to determine who were genuine refugees and resettle them as quickly as possible. It also said detainees must be kept fully informed about their status.
The report added that "a large number of assaults were committed during the disturbance, mainly on transferees" and no charges had yet been laid.
It said there was a "major task ahead" to rebuild trust between the centre operators and inmates, and charges against those responsible "will play a large part in restoring that trust".
Australian Immigration Minister Scott Morrison said Canberra would abide by the report's recommendations, with "significant improvements" already initiated at Manus and the first refugee determinations handed down last week.
He told a press conference the violence at the camp, which is under PNG jurisdiction, represented a "terrible, tragic and distressing series of incidents" but it would not have occurred but for protests.
"There would have been no incident that night had there been no protests, I think that is clear to say," he said.
"But the protests in no way could ever justify what happened to Mr Barati or the other serious violent acts perpetrated on that night."
It is not known whether the Iranian had taken part in the protests.
Morrison said it was up to PNG police to lay charges over the violence, and all information obtained in preparing the report had been handed over to local authorities.
The latest immigration department figures, to the end of April, show there were 1 273 would-be refugees being held on Manus Island.