A 39-year-old prisoner was found dead in his cell at Corradino prisons on Wednesday afternoon.
The police said the man was found dead shortly after 5pm in Division II.
The police are investigating and a magisterial inquiry has been appointed. The prisons are also holding an internal inquiry.
The man was awaiting trial for attempted murder.
This is the second such case in three months.
In December, a 26-year old inmate was also found dead at Corradino Correctional Facility. A magisterial inquiry and internal investigation had also been ordered in that case.