An Aboriginal man who died in custody in 2015 repeatedly screamed for help and said he could not breathe before he became unresponsive and could not be revived, an inquest has heard.
David Dungay jnr, 26, died in the prison hospital at Sydney's Long Bay jail on the afternoon of December 29, 2015 after he was removed from his cell by a specialist riot response unit because he refused to stop eating biscuits.
Six officers from the Immediate Action Team forcibly moved Mr Dungay from Cell 71, which did not have video cameras, to Cell 77, which was under video surveillance, just after 2.42pm.
In an eight-minute interaction recorded by a handheld video camera, officers can be seen running into Mr Dungay's cell after a call of "go go go" and pinning him down to the bed and then the floor.
Mr Dungay gasps for air, screaming and crying and repeatedly saying "I can't breathe".
As he is escorted down a corridor with his head held down, a sock on one foot and the other one bare, he again says he can't breathe.
He is taken to a new cell and pinned face-down on to the bed, with an officer's knee on his back. He receives a shot of the sedative midazolam in his buttocks as he is held down.
David Dungay being restrained by six officers from the Immediate Action Team before being moved to a different cell. Credit: NSW Corrective Services
When Mr Dungay again says he can't breathe, officers respond, "If you can talk you can breathe". About a minute later, he is unresponsive.
On Monday, at the opening of a two-week inquest at Sydney's Downing Centre courts, Deputy State Coroner Derek Lee extended his personal condolences to Mr Dungay's family for their "incredibly sad and devastating loss".
David Dungay, 26, died at Long Bay jail in December 2015.
Counsel assisting the coroner, Jason Downing, said Mr Dungay had been diagnosed to be acutely psychotic with auditory hallucinations and his mental health had deteriorated significantly while he was in custody. Mr Dungay was also being treated for diabetes, which he had lived with for many years.
Mr Downing said an emergency physician expert, who is expected to give evidence at the inquest, was "highly critical" of the CPR given to Mr Dungay before paramedics arrived at the jail.
Although initial attempts at resuscitation were of the "highest standard", efforts by Justice Health staff failed to provide consistent cardiac massage and ventilation, the inquest heard.
As a result, efforts to revive Mr Dungay were "effectively without value" and "incompatible with survival".
"Whether Mr Dungay would have survived with adequate resuscitation by the Justice Health staff is not clear," Mr Downing said.
"Whatever chance Mr Dungay had was lost by the inadequate and interrupted care he received from Justice Health."
Mr Downing said an autopsy report listed Mr Dungay's cause of death as "unascertained".
However, after his death, Corrective Services made "a number of changes" to inform staff about the risk of positional asphyxia when restraining inmates.
"It would appear that Mr Dungay had a cardiac arrest as a result of being restrained in the prone position by the IAT members," Mr Downing said.
"It is possible, though unclear on the expert evidence, whether he may have suffered a cardiac arrhythmia with a possible contribution from one or a combination of the anti-psychotic medications he was on."
David Dungay could be heard saying "I can't breathe" about one minute before he became unresponsive. Credit: NSW Corrective Services
The inquest heard Mr Dungay was in custody after being convicted of robbery in company with wounding, aggravated attempted sexual intercourse and assault occasioning actual bodily harm.
He was sentenced to a minimum of six years and six months behind bars, with a further term of three years, and would have first been eligible for parole on July 20, 2014. However he was not recommended for parole because of his failure to engage in programs.
Barrister Simeon Beckett, representing the Corrective Services Commissioner, offered his sympathies to Mr Dungay's family.
Banners reading "Justice for David Dungay" outside the Downing Centre Court in Sydney on Monday. Credit: AAP
"The Commissioner for Corrective Services deeply regrets the death of Mr Dungay," Mr Beckett said, adding that policy and procedural changes were made in the wake of Mr Dungay's death.
Angry family members interjected at several points, including when a barrister for three prison guards said Mr Dungay had not died at their hands.
"You're a joke," one man shouted.
As the inquest adjourned for lunch, a smoking ceremony was held outside the court building.
Leetona Dungay, David's mother, said it was difficult to watch the video of her son's final moments. Credit: AAP
Mr Dungay's mother, Leetona Dungay, said it had been hard to watch the footage of her son's final moments but she had to do it to get justice.
"If no mother does that, she didn't care about her son. But this mother does," she said. "I will do anything to get justice."
The inquest continues.