A Papua New Guinean man employed by the The Salvation Army led the “brutal beating” that killed Iranian asylum seeker Reza Barati during the riot on PNG’s Manus Island, an independent review has been told.

Immigration Minister Scott Morrison on Monday released the long-awaited review – conducted by former public servant Robert Cornall – into the February violence.

He said the government had accepted all 13 of its recommendations.

• Click the advisor owl to read all the recommendations 

The review found there was no particular factor that caused the violence.

“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 says.

But it says frustration and anxiety over a lack of information about resettlement policies was a key contributor to the tensions.

The review says Mr Barati, 23, suffered a severe brain injury “caused by a brutal beating by several assailants”.

The review interviewed an eye-witness to the attack.

“He said the attack 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.”

At least 69 people were treated for injuries as a result of the violence.

Mr Morrison described the events as “terrible and tragic”.

He said the review’s recommendations had either already been implemented, or were in the process of being implemented.

The report reveals Mr Berati was alive when he was treated by medical officers at an emergency triage centre on a wharf.

“But the medical staff knew from his injuries that he was not going to survive,” the report quotes a medical officer as saying in a formal interview.

Mr Morrison says the riots were the result of “increasing tensions within the centre and the transferees’ frustration and anxiety caused by anger at being brought to Papua New Guinea”.

The report found that the tensions were aggravated by “the antagonism that had been developed between some transferees and PNG nationals employed at the centre and supporters in the local community. Some transferees treated PNG nationals employed in centre in a disrespectful and racist manner, and criticised their country.”

The inquiry was conducted by former secretary of the Attorney-General’s department, Robert Cornall.