A spokesperson for Australia's asylum seeker resource centre says the story put forward by Australian and Papua New Guinea authorities following violent clashes at an asylum seeker detention centre in February is continuing to crumble.
On Tuesday, Fairfax media released a video that shows security guards at the Manus Island centre attacking asylum seekers the night before Reza Berati was killed.
The video appears to contradict statements made by Australia's Immigration minister, Scott Morrison, that guards were unarmed, and that only warning shots were fired in the air.
Pamela Curr of the Australia's asylum seeker resource centre says this latest revelation further dents the authorities' credibility.
"Well and truly, the cat is out of the bag. We knew a few days after that attack that what had happened on that terrible night of the 16th and 17th was very much at odds with what the minister was telling us. The minister had to play catch up."
Ten weeks on from the clashes on Manus Island, no charges have yet been laid.