Inmates at four South Australian prisons will be confronted with the faces of cold case murder victims in what authorities hope will compel them to come forward with information.

SA Police Deputy Commissioner Scott Duval said criminals or those involved in the criminal world often held the key to solve the puzzle.

He said more than 80 calls had been made by prisoners within the correctional system to police since Operation Persist – a targeted campaign to resolve cold case murders – was launched in March 2015.

“People in the criminal environment often know about other things going on in a criminal environment,” he said.

He said new television screens were being installed in the Adelaide Remand Centre, as well as Mobilong, Yatala and Port Lincoln prisons, and would display constant images of more than 100 murder victims.

Playing cards were handed out in 2015 encouraging people to come forward with information. Photo: ABC News

New playing cards have also been issued in jails for inmates after a successful trial of playing cards asking prisoners for help to solve cases was introduced in 2015.

Since Operation Persist started, police have secured two cold case convictions over the 1998 murder of Dale McCauley and the 2012 murder of Jayson Doelz.

A further four cold case murders are before the courts, including the 1994 National Crime Authority bombing of Detective Sergeant Geoffrey Bowen and the 2005 murder of Martin Meffert.

“We know that public information is critical to solving some of these homicides and in effect our successes to date have been resolved with people being convicted of cold case homicides,” he said.

“While it is absolutely devastating to lose a family member, there can be some solace out of the fact that people are held accountable for that murder and are now serving a term of imprisonment.”

Correctional Services Department chief executive David Brown said the department was “absolutely committed” to the initiative.

“We believe the people coming into contact with our system may have information that will assist SAPOL to resolve these long-standing unsolved crimes and give some closure to the victims of those crimes,” he said.

“Every year, more than 6000 people pass through our prison system and more than 7000 people are under supervision in the community on any given day.

“Operation Persist provides those people with a conscious jogger – a reminder that these cases remain unsolved and they may have that one piece of information that fits into a puzzle that SAPOL are building in their investigations.

“The TV screens in our waiting rooms for visitors entering our prisoners or for offenders reporting to community corrections centres for supervision or the playing cards prisoners are using in their recreation time, just act as a constant reminder that there is no closure for the families of these victims.”

Those intimately involved in crime often hold the key

Crime Stoppers SA chair Sharon Hanlon said it was common for vital information in a cold case murder to come from somebody who was “intimately involved with the criminal fringe”.

“They’re really important tactics to keep these issues top of mind and directed to our target audiences in particular,” she said.

She said the Crime Stoppers service did provide complete anonymity and was a bridge between the community and police.

“We’re hopeful that tactics such as these, which are considered unique – some of them are groundbreaking, they haven’t been tried elsewhere – will give us an additional piece to the puzzle and resolve some of these very long-standing crimes,” she said.

Commissioner of Victims’ Rights Bronwyn Killmier said the initiative was supported by victims.

“Our hope is that it will encourage people to come forward and shed some light and help them recover from the crimes,” she said.

Anyone with information about a cold case murder is encouraged to call Crime Stoppers on 1800 333 000.

–ABC