A New Zealander working as a guard at the Manus Island detention camp has been identified by witnesses as taking part in a fatal attack on an Iranian asylum-seeker, Australian media reports.
An official report into the death of Rezra Barati during riots on the PNG island in February has been released.
It found a local Salvation Army worker led the attack on Mr Barati, 23, who was hit with a stick, kicked and had a large rock dropped on his head.
It laid the blame with guards employed by security firm G4S and paid for by the Australian taxpayer, police officers from Papua New Guinea and local Manus Island residents.
The independent report, released yesterday, confirmed gruesome details about the violence carried out over two nights on February 16-18, including a detainee having his throat slashed and another being beaten so badly he lost an eye, The Age reported.
The violence came after rising tensions between the mainly Iranian asylum-seekers and PNG nationals working there.
The key witness to Mr Barati's killing told the report's author Robert Cornall, an Australian former senior public servant, that Mr Barati was in the internet room when the unrest started. He went outside and the Salvation Army worker "hit him twice with a very long stick", The Age reported.
"When he fall down, more than 10 officers passed him and all of them, they kicked him in his head," the witness said. "It was including PNG locals, PNG guards and Australian expats. The last one of the them he put a very big stone at his head."
Australian Immigration Minister Scott Morrison said the only expatriate guard implicated by multiple witnesses was a New Zealander.
Mr Morrison vowed to maintain his hardline approach on asylum seekers despite "great regret" that urgent security upgrades were not made to the Manus Island detention camp before the riots.
Mr Morrison said the violence would not have occurred if protests by asylum seekers had not taken place, but this did not justify what happened to Mr Barati and other the victims.
Mr Morrison referred all questions about prosecution of suspects to the PNG police.