On the edge of a hillside overlooking a lush green valley lies the grave of two teenage school girls.
The three schoolgirls were ambushed on their way to school
The double grave is covered in wreaths, including one from the Indonesian president.
On the day we visited it was also surrounded by mourners; family and friends gathered to mark forty days since the girls' death.
The distraught mother of fifteen-year-old Afita talked to a photograph of her daughter which had been placed by the headstone. "Be at peace," she said "may God forgive your sins."
There was nothing peaceful about the way Alfita and her friend died.
They were ambushed on their way to school and murdered. Their bodies were mutilated. Two severed heads were later found near a police post and a third was left on the porch of a house in Christian community on the outskirts of town.
The attackers seemed to be sending a chilling message.
Poso is no stranger to violence. The area was the scene of bitter fighting between Christians and Muslims five years ago. More than a thousand people were killed before a peace agreement was brokered in December 2001.
The ruins of burned out buildings - churches, mosques and houses - bear silent testimony to the ferocity of the battles fought here.
Adnan Arsal: "I think there's some sort of agenda to discredit Islam in general"
One of the worst single incidents took place at Walisongo Islamic boarding school, nine kilometres out of town. A Christian group attacked without warning. At least a hundred Muslims were killed.
The school has long since been abandoned. Tangled vines and bushes have grown up through the wreckage. Cows graze lazily on the grass which covers the rubble.
Ilham, a young assistant teacher at the time of the attack, showed me around the grounds. He took me to a hole at the back of the school where he said eight badly burned bodies had been found.
Ilham fled to the jungle but was later captured. He managed, eventually, to escape, but not before he'd been tortured. His back and arms are covered in thick dark scars.
The experience changed him forever. He became involved with a group of mujahedin fighters.
The conflict in Poso attracted militant groups from other parts of Indonesia who came to train local recruits for what they believed was a jihad, a holy war. "It was difficult to get to know them," Ilham told me;" They didn't give their real names. They were very secretive. At that time, during the conflict, we welcomed anyone who came to help us."
So should the beheadings of the schoolgirls be viewed as part of a continuing cycle rather than an isolated act of brutality?
Despite the peace deal, sporadic violence has continued. The police have said they think an organised group is to blame for the latest killings, but they've given few details. Because the most recent attacks appear to be targeting Christians, some local Muslims have found themselves under intense scrutiny.
Adnan Arsal, was a signatory to the 2001 peace agreement, but he is known to have links to radical groups. The police recently raided the school which he runs. Mr Arsal says he and his colleagues were being unfairly victimised.
Homes burning in violence-wracked Poso in December 2001
"I think there's some sort of agenda to discredit us and to discredit Islam in general," he said, "so the blame will fall on Muslims and we'll be labelled terrorists. But look at our school. Do you really think that anyone here could carry out such a killing? Clearly outsiders did this."
Outsiders have certainly seen potential in Poso before. Sidney Jones, of the International Crisis Group, said there are clear links between those who fought to defend Muslims during the height of the conflict in Sulawesi and those who have targeted westerners in Bali and Jakarta.
"From the very beginning the reason Indonesians joined terrorist movements was because of local issues, not Iraq or Afghanistan or Palestine." So, she says; "the best way to prevent further terrorist activity in Indonesia is to make sure that communal tensions between Christians and Muslims are well handled."
But the murder of innocent schoolgirls has added new layers of grief, fear and anger to the old. Poso's fault lines have been exploited before. It is in the interests not just of Indonesia, but also of the wider world to make sure it doesn't happen again.
Rachel Harvey's report will be screened by Newsnight on Tuesday, 20 December, 2006. Newsnight is broadcast every weekday at 2230 GMT on BBC Two.