While guards with private security company G4S, which provides security inside the centre, were reportedly to be using only riot control tactics. An investigation is under way into fatal clashes at Manus Island. Operation Sovereign Borders commander Angus Campbell is on the island assessing security. Credit:Jason South Then there were the claims that locals in the area joined forces with security staff to fight with asylum seekers, who were allegedly trying to escape. Immigration Minister Scott Morrison has confirmed that PNG police fired shots as well, but said ''there was no suggestion they fired at asylum seekers''. But reliable forensic evidence as to who did is likely to come from the asylum seeker who was shot.

Fairfax has learned that X-rays taken of the man's wound on Tuesday reveal a projectile still wedged against his hip bone. And that the shape suggests projectile from a large calibre weapon such as those used by police. Initially there had been rumours that the wound might be from small pellets from a shotgun possibly fired during the riot. But Manus Island doctor Otto Numan, who X-rayed the victim, and has seen a number of shotgun wounds said: ''It's not a pellet. I have seen pellet wounds.'' He said it appeared to be large and in his experience did not match the same type of injuries from a shotgun.

An operation to extract the projectile could be problematic, Dr Numan said. ''If this was a local case we would admit him, dress his wound and then in most of the times like this we would not go in and operate. We would wait for the foreign body to work its way out. It may take several years,'' he said. If evidence emerges of heavy weapons being used during the riot it could indicate PNG's feared Mobile Squad police may have been responsible. The squad is armed with military style automatic weapons and has regularly been implicated in the killing of suspects. Its presence on the island has already been criticised by human rights activists and locals. It also adds weight to claims about the inability of PNG authorities to handle such an operation.

But there also the unlikely chance that someone other than the police may have fired a weapon. The detention centre is in the middle of an official Naval base, which includes residential housing for naval staff. Dr Numan said the injured man, who had been able to walk but was in some pain, did not say how he came to be shot. ''He was polite about asking for treatment,'' he said. Dr Numan said that after being X-rayed the asylum seeker was taken back possibly to a clinic at the detention centre. He has now been flown to Port Moresby for treatment. Mr Morrison on Wednesday said: ''There's no suggestion those shots (from the police) were the ones that involved the individual being shot in the buttocks either. ''You need to be careful not to connect dots here that I haven't connected.