Police investigating the killing of Reza Barati on Manus Island have for the first time been given graphic statements from the asylum seekers who witnessed the slaying, with two Australians emerging as suspects.

The statements were handed to police on the island by the Sydney lawyer who obtained them before he was deported from Manus Island on Friday, having been shut out of the detention centre in defiance of a court order.

A witness to the violence at the Manus detention centre. Credit:Alex Ellinghausen

The deportation thwarted a planned meeting between the barrister, Jay Williams, key investigators and the asylum seekers, who until now have been too scared to give authorities their account of the slaying of Mr Barati, and injuries to more than 60 other detainees on March 17.

But Mr Williams gave the investigators a letter to pass on to the witnesses. The statements are from three asylum seekers, including his roommate, who say they saw how Mr Barati died; one who was attacked, then shot in the buttocks when he fled and bashed again; and one whose throat was slashed while he says two men pinned his arms.