A group of experts mandated by a French inquiry to probe the 1994 downing of Rwandan leader Juvenal Habyarimana's jet is due to say Tuesday where the fatal ground-to-air missile was fired from.

This detail could prove crucial in establishing the credibility of two rival accounts of the attack, which was one of the triggers that unleashed a genocide that left around 800,000 Rwandans dead.

It could also revive tensions between Paris and Kigali, whose relations broke down in 2006 when a French judge accused members of now-President Paul Kagame's regime of involvement in the assassination of his predecessor.

The slain pilots on board Habyarimana's Falcon 50 jet were French citizens, giving anti-terror judge Jean-Louis Bruguiere grounds on which to investigate.

His probe concluded that a small commando team from Kagame's then rebel Rwandan Patriotic Front (FPR) infiltrated the area around the airport and fired the missile that downed his enemy's plane.

Eight Rwandans have been placed under investigation for the attack.

In contrast, a parallel Rwandan inquiry found the attack was launched from a base held by loyalist forces from Habyarimana's Rwandan Armed Forces (FAR), targeting their own leader because he was seen as too moderate.

What is sure is that, following the attack, hardliners from the slain president's Hutu ethnic group, led by members of his inner circle, began to slaughter members of Kagame's Tutsi minority.

Kagame's Tutsi FPR eventually managed to overthrow the Hutu-led regime, and peace has returned to Rwanda, but relations with France remain strained.

Some in Rwanda accuse French forces, which were close to Habyarimana's forces, of siding with the Hutu death squads, a charge angrily denied by French officials from the era.

Relations were further strained by Bruguiere's investigation, which caused Kigali to temporarily break off ties, but since Nicolas Sarkozy was elected French president in 2007 he has worked to improve relations.

Kagame and Sarkozy have now visited each other's capitals and diplomatic relations have been restored, but ongoing judicial probes in both countries are still a source of disagreement.

Six French experts, who were able to visit the scene of the attack, have attempted to establish the missile's trajectory and hence launch site.