ACT police are investigating the death of a man inside Canberra's only jail, which occurred on Sunday afternoon.
The detainee died in Alexander Maconochie Centre (AMC) after what the Justice and Community Safety Directorate (JACS) described as an "incident".
"The Justice and Community Safety Directorate can confirm that an incident occurred at the Alexander Maconochie Centre at approximately 1pm on February 26," JACS said in a statement.
"While ACT Policing investigates the incident, the AMC has been placed into lockdown."
JACS said the man had been found by corrections officers who were undertaking "routine checks."
"ACT Policing has notified the next of kin, and we extend our condolences to the family and friends of the deceased," the statement read.
It is the second death at the jail in just over a year, after a 27-year-old man was found dead in his cell in February 2022.
The death on Sunday also comes after a number of incidents in the past few years, which have led to recommendations for changes to the jail's security processes and systems.
In 2018, the death of Indigenous prisoner Steven Freeman prompted calls for changes to "mustering" processes in Canberra's jail.
In 2019, a coroner found that Canberra prisoner Mark Anthony O'Connor had overdosed on ice despite being under a 23-hour-a-day lockdown.
In 2020, then-corrections minister Shane Rattenbury asked questions about the security at AMC after it was found a detainee had remained undiscovered for 45 minutes after being stabbed in the head and neck.
And last year, a "Hollywood-style" prisoner escape prompted calls for changes into how both transfers and escapes were handled by staff.
ACT police said a report on the death of the detainee would be prepared for the coroner.
