Investigations began after a 26-year-old prisoner was found dead overnight in his cell southwest of Brisbane.
The detainee was remanded on suspicion of assault and was found dead in his double room at Arthur Gory Prison at around 2:05 am.
A police officer performed CPR and the Queensland Ambulance Service was called, but the man was unable to resuscitate.
The Queensland Correctional Service is investigating death and will assist in preparing a report for coroners, Courier-Mail reports.
“Our condolences are directed at the man’s family and friends,” said a QCS spokesman.
“Support is provided to the corresponding officers and colleagues at the Arthur Gory Orthodontic Center.”
The prison south of Brisbane has been closed since August after two police officers in the training program were tested positive for the coronavirus.
In September, cells were flooded, destroyed, and ignited after prisoners complained about the ongoing blockade.