Despite concerns about tensions in the centre, some of the suspects in Mr Barati's death are believed to be still working there alongside many other staff thought to have taken part in the violence.

The revelations came as further claims emerged about the clashes, including how desperate asylum seekers tried to tie bed sheets to the door handles in their rooms to prevent their attackers getting in.

In an account obtained by Fairfax Media, an Iranian asylum seeker said two detainees were blinded, one had his eye ''removed'' and one machete victim was ''cut so badly all around his neck like they meant to cut his head off''.

Manus Island provincial police commander Alex N'Drasal said on Thursday he hoped soon to arrest three to four men and charge them with murder.

''Hopefully either this week or early next week, we are going to make arrests,'' he said. ''We are looking at three to four guys to be arrested and charged. We'll probably charge them with murder.''

He declined to say who the men were, including whether they were locals or foreigners, or whether they were local staff at the centre.

He said he believed most local staff were back at work, including security staff, a direction that contradicted statements by Immigration Minister Scott Morrison.

Asked whether this included the three to four suspects, Mr N'Drasal said he was not certain but added: ''I believe they are still there working.''

He said he had given instructions that none of the detention centre staff should leave Manus Island while the police investigation was running and therefore it was proper they should continue working.

Mr Morrison said through his spokeswoman: ''I am advised there are no locally engaged staff deployed as security officers within any of the compounds.''

Greens senator Sarah Hanson-Young said letting workers involved in the violence back into the centre was a ''recipe for disaster''.

A recording of the Iranian detainee's statement on Tuesday and an English translation described disturbing new details about the incident. The material was provided by Senator Hanson-Young and by a second, independent source.

The detainee said Mr Barati's alleged killer was a local Salvation Army worker.

He said machetes and guns had been used in the clashes, and that ''people were attacked in their beds and their heads were cut open'', leaving ''blood on closets, pillows and walls''.

He told of a detainee being carried to safety by an Australian guard when he was hit on the head with a pole by a local guard.

''As he lifted his head up, the PNG guard recognised him as a friend who had been giving him his cigarettes every day. He was shocked and said, 'Sorry, sorry my friend.'''

with Michael Gordon and Rory Callinan