An Aboriginal man has died at Acacia prison in Western Australia, the second man in the past month.
The 19-year-old was found unresponsive in his unit at the prison on Saturday and taken to hospital where he died on Monday.
In a statement, Serco Australia, which runs the privately-owned prison said the man's death will be subject to a Coronial Inquest.
"Attempts were made to revive the prisoner before he was transferred by ambulance by hospital," the statement read.
"Staff at Acacia prison have remained in contact with the man's family during this period and Serco acting prison director Craig Moody has offered his condolences to the family on behalf of all prison staff.
"The prisoner's death will be subject to a Coronial Inquest, which will examine the circumstances surrounding his death.
"Serco will also assist a Department of Justice review into the prisoner's death."
The WA Department of Justice said it would not comment on the death as it is now subject to an investigation.
It is the second death in custody of an Aboriginal detainee at Acacia prison in the past two months.
Early last month, a 40-year-old Aboriginal male prisoner was found collapsed at the prison, and was later pronounced dead at hospital.