Nineteen South Australian prison guards are attempting to have a coroner removed from investigating the death in custody of an Indigenous man after seven guards lost a bid to avoid giving evidence at the inquest.

The inquest into the death of Wayne Fella Morrison has not heard any new evidence since last December, when seven guards who travelled in a transport van with the 29-year-old man argued they should be excused from giving any evidence that could implicate them in either criminal or internal disciplinary proceedings.

Morrison, a Kokatha, Wirangu and Wiradjuri man, was blue and unresponsive when he was pulled from the transport van on 23 September 2016 and did not regain consciousness before dying in hospital three days later.

He had been placed face-down in the van after being restrained by a dozen officers in an incident caught on CCTV at Adelaide’s high security Yatala Labour Prison.

The prison guards have challenged the inquest in the supreme court, arguing that they should have a right to silence when being asked to give evidence that could lead them liable to civil or disciplinary penalty.

They have also argued that the deputy state coroner, Jayne Basheer, should be removed from the inquest, saying there is a risk of apprehended bias because she had, at one point in her career, acted in a matter for which her fees were paid by the Correctional Officers Legal Fund.

The hearing was listed for the supreme court in Adelaide on Tuesday and is scheduled to run for three days.

Basheer and the coroner’s court are opposing her removal. Morrison’s family, which are not listed as a party to the case but have been granted the right to make a written submission, have argued that Basheer be able to stay on as coroner to ensure the inquest is concluded without further delay.

Morrison’s sibling Latoya Rule said their family had waited three years and two months for answers about their brother’s death. If Basheer was removed as coroner, that wait would be even longer.

“We stand by the coroner staying on for reasons of timeliness,” Rule said. “We just want transparency.”

The inquest began in August last year and has already held several weeks of hearings, including evidence from health providers, experts and some of the prison guards. Those who were travelling in the van with Morrison have not given evidence.

Rule said they and their family wanted the inquest to be concluded as soon as possible so recommendations could be made.

“I am more concerned about what recommendations are going to be made and how that will help us in seeking further justice for Wayne,” they said. “At the end of the day someone has died, and I feel like what’s happening now is taking away from the death of Wayne.”

Rule said their family would be supported in court by community members but that even with that support, having to continually attend court hearings for deaths in custody was taking its toll on both Morrison’s immediate family and the broader Aboriginal community.

That community is currently grieving the fatal police shooting of Kumanjayi Walker in the Northern Territory remote community of Yuendumu.

“We don’t wake up every day wanting to all come down to the court to hear about the death of a loved one,” Rule said. “We want to move on with our lives, we want to grieve and to heal ... It’s not that I am against this [legal] process, we support due diligence, but I would rather know what happened to Wayne.”