Papua New Guinea's Correctional Services department is conducting an investigation into the sudden unexplained deaths of two senior staff, who died while at a conference in Goroka last week.
The dead men, the Correctional Service Commissioner Martin Balthazar and his Deputy Commissioner of Corporate Affairs, David Melange, died two days apart.
Our correspondent in PNG, Todagia Kelola, says there is widespread speculation that they may have been poisoned, perhaps by disgruntled former prisoners.
He says this is why the government has funded the department's investigation.
"It is really unusual for two people to die while attending a conference and both of them, according to those who were there, died because of heart attack problems. There is something really fishy in their deaths."
Todagia Kelola says there is no police investigation as yet.