Wayne Thomas Kerle, 68, was found lying dead in the police vehicle when it arrived at Brisbane City Watch House on December 27, 2022.
Deputy State Coroner Stephanie Gallagher handed down her findings this week following hearings in August 2024.
Ms Gallagher was shown police body-worn camera footage of Mr Kerle  twice falling forward onto his stomach and being dragged on the ground by his arms that were still cuffed to the rear.
He was yelling for help.
Paramedics had decided against taking Mr Kerle to hospital during his arrest on suspicion of drug possession at a unit in inner Brisbane suburb of Fortitude Valley.
Police instead told him they would take him to a station to charge him and "you'll be out of custody in an hour".
During the 30 minutes it took to get Mr Kerle out of the unit and into the back of a police van, he asked the officers for help amid a string of insults.
"I can't breathe," he said.
When officers told Mr Kerle he could breathe and talk, he replied "you're gonna kill me".
"After the abuse you just hurled at us there is no way I'm taking the cuffs off," an officer told him.
Mr Kerle had already informed police he had chronic obstructive pulmonary disease, which causes people to have trouble breathing, and was having severe symptoms.
There were no cameras in the back of the police van to monitor Mr Kerle during the five-minute drive and officers did not directly observe him.
At the watch house officers called an ambulance when they saw Mr Kerle had turned blue.
An autopsy was unable to ascertain his cause of death, but Ms Gallagher found "physical exertion during his interaction with police and possible positional asphyxia" played a role.
"Mr Kerle's significant pre-existing natural diseases ... along with the physical and psychological stressors of the arrest process, likely exacerbated his underlying medical conditions, leading to his death," Ms Gallagher said.
She supported the Queensland Police's ongoing installation of CCTV audio and video capacity in all police vans.
"I recommend the continuation of post-arrest care training to officers regarding the appropriate identification of a prisoner suffering a medical issue or behavioural disturbance," the coroner said.
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