The killers congregate at roadblocks under the lush hillsides, feeling safety and power in numbers. They check cars and pedestrians, looking for rebel Rwandan Patriotic Front (RPF) infiltrators or members of the country's Tutsi minority, which for these men are one and the same.
They operate under the noses of the French intervention forces who were sent to protect the very people that the killers are searching for. They are numerous in an area of the south-west that the French have declared a 'safety zone' for civilians fleeing RPF advances and extremist militias.
Since the slaughter in Rwanda first hit the headlines last April, these young men have become known in the shorthand of daily journalism as 'Hutu extremist militias'. More rarely have they been identified by one of their official names, Interahamwe - often translated as 'Those who attack together'.
'The name comes from an old song,' said one Rwandan and broke into a melody. 'Rise up Rwanda, you are supported by Interahamwe, those who join together in common cause.'
Jacques is 27 and a former civil servant from Kigali. He is soft-spoken and well-dressed. He is now living with relatives in Cyangugu near Rwanda's southern border with Zaire. He does not seem the sort of person capable of murder but he has personally killed at least 10 people and was a member of a group that tortured and murdered dozens more.
His proof of Interahamwe membership is a card decorated with a red, green and black border and bearing the logo of the former ruling MRND party of President Habyarimana. 'Before the president's death the Interahamwe was only the MRND youth wing. We were just young people, not militias. Originally we were not together for fighting but for thinking,' Jacques said.
It was a small step from 'thinking' to genocide. The death in a suspicious plane crash of President Habyarimana on 6 April was the pretext for the militias to launch an orchestrated campaign of killings against Tutsis and moderate Hutus. Jacques was there.
You killed entire families?
'Yes. They were RPF members.'
Women and children too?
'Yes, everybody was killed because if one escaped he could join the RPF and come back and attack us. In some cases children were spared and were taken to the Red Cross. But if their father or brother was an RPF member or supported them, the whole family was killed. Even the children.'
Do you feel sorry that you killed Tutsis?
'No, I can't say that I feel sorry.'
Revulsion at Jacques' testimony is tempered by the awe for the sheer audacity of what the Interahamwe tried to do. Their aim was to exterminate.
Current wisdom has it that what is happening in Rwanda is the result of a political war, devised by the anti-Tutsi Hutu extremists from the late president's entourage who nurtured the Interahamwe and trained them in the art of killing with grenades, spears and machetes.
But politics is only part of the story. Events in Rwanda have been driven by ethnic hatred picked up over centuries when a small Tutsi aristocracy ruled over Hutu farmers.
When the Belgians took control of Rwanda in 1919, the Tutsis - taller and more European in appearance - were feted while the Hutus became a majority second-class. As independence approached, however, the Belgians shifted their allegiance and a Hutu uprising in 1959 settled old scores. As many as 100,000 Tutsis were massacred and 200,000 more forced to flee. The children of those Tutsis formed the RPF and, since 1990, have been fighting, not for a complete takeover, but for the right to return home and share power.
At the heart of the Hutu justification for their actions of the last three months is the unshakeable belief that the Tutsis want to return to the domination of the past. This collective mind-set owes much to four years of government propaganda that painted the RPF as murderers and the Tutsis as their instruments of death.
In the first weeks of slaughter, Jacques and his group were egged on by extremist radio broadcasts which told Hutus 'When you kill the rat do not let the pregnant one escape. We made the mistake 30 years ago of letting them flee into exile, this time none will escape.'
The legacy of the years of propaganda is a blurring of fiction into fact. 'In Kigali there were Tutsi and some Hutus who had prepared themselves with guns and machetes. Then they started to attack Hutus. It was only then that the Rwandan military, the parties and the youths understood that we had to defend ourselves,' said Jacques.
'From that moment we began to search houses. Every time we found weapons in a civilian house we asked them to explain what they were doing with weapons. If they could not explain we put them in the holes that they had prepared.'
These holes, according to Jacques, were 3ft in diameter and 90ft deep. The physical impossibility of digging such a shape with handtools mattered little to Jacques. He was sure that they existed and had no doubts as to their purpose. 'It wasn't a toilet or anything else. Those holes were for Hutu bodies. It was part of the Tutsi plan to kill the Hutus.'
Today, Jacques and many other Interahamwe youths have retreated with the civilians now seeking French protection. The recent battlefield success of RPF has done little to force them underground. If anything it has only concentrated them in the shrinking government controlled areas of western Rwanda, where they seek more victims to appease their anger and mollify their fear.
And they are angry and afraid. Defeat has been breathing down on them since the RPF took Rwanda's capital, Kigali and its second city, Butare, last week.