Accused of commanding a presidential guard implicated in high-profile murders during the Rwandan genocide, Protais Mpiranya is the top priority for investigators following this year's arrest of a fellow alleged war criminal.
On the run for 20 years, charged with war crimes, genocide and crimes against humanity, Mpiranya is the most sought of the six remaining fugitives indicted by an international tribunal into the 1994 slaughter which left some 800,000 dead.
He was second on the wanted list until the arrest of alleged genocide financier Felicien Kabuga near Paris in May.
France's top appeals court ruled Wednesday that Kabuga, who had evaded capture in several countries, should be transferred to a UN tribunal in Tanzania to stand trial.
But Mpiranya, who is believed to be around 60, remains at large.
At the time of the genocide he commanded the presidential guard, a feared outfit accused of targeted assassinations during the 100-day massacre of Tutsis and moderate Hutus.
In particular, Mpiranya was allegedly among those who ordered the murder of then prime minister Agathe Uwilingiyimana, 10 Belgian soldiers protecting her, and several other leading politicians and their families on April 7, 1994, in the early hours of the genocide.
Wave of assassinations
The evening before, a plane carrying Rwanda's president Juvenal Habyarimana had been shot down on its approach to Kigali International Airport.
The president had just returned from a regional meeting in Tanzania, where he agreed to push ahead with the terms of the 1993 Arusha Accords which were meant to end a three-year war between the Hutu government in Kigali, and a Tutsi rebellion.
Following Habyarimana's assassination an emergency meeting was called between top brass of the Rwandan Armed Forces, top police officials, the UN military and civilian leaders.
The latter made the case that Uwilingiyimana, a moderate Hutu and Rwanda's first female prime minister, had legal authority to take control of the country and suggested she make a national address to that effect.
But Rwanda's radical Hutu leadership had other ideas.
On the morning of April 7 Mpiranya and two other military officials "ordered their subordinates... to search for the prime minister, Agathe Uwilingiyimana, in order to kill her", read the prosecutor's indictment for the former International Criminal Tribunal for Rwanda (ICTR).
Uwilingiyimana was sexually assaulted and murdered and left in the street, naked, in full view of passersby. The savage attack was overseen by a captain of the battalion of the presidential guard, the indictment said.
But her murder was only the first in a wave of assassinations targeting prominent figures and politicians who supported the Arusha Accords.
Among those killed were the president of the Constitutional Court, the minister of agriculture, the minister of information, and the vice-president of the Social Democratic Party, who was being considered for the post of president of the transitional National Assembly.
The killings aimed "to create a political vacuum and derail the implementation of the Arusha Accords", read the indictment, which directly implicated the presidential guard in the attacks.
'He is hiding'
Mpiranya hails from the former province of Gisenyi, in northern Rwanda, also the homeland of Habyarimana and several other top-ranking hardline Hutu military officials.
After graduating from military college in Kigali in 1983, he was assigned to the national police force.
In 1991, as the army was fighting the rebels of the Rwandan Patriotic Front (RPF), led by today's President Paul Kagame, Mpiranya was transferred to the presidential guard battalion and two years later was promoted to commander.
In July 1994, after the army's defeat at the hands of the rebels brought about the end of the genocide, Mpiranya began a long journey into exile that would take him to several African countries.
In 1998, he fought alongside Congolese forces in a campaign against rebels backed by Rwandan troops, said the NGO African Rights, which has studied the genocide.
According to press reports, he was later sent to Zimbabwe on behalf of the Democratic Forces for the Liberation of Rwanda (FDLR), a militia partly composed of former Hutus implicated in the genocide, and accused of exploiting the mineral wealth of eastern Democratic Republic of Congo.
"Through our intensified investigations over the past three years, we have come to a solid understanding of Mpiranya's movements and where he is hiding," said Serge Brammertz, the prosecutor of the Mechanism for International Criminal Tribunals (MICT), the body charged with completing the work of the ICTR which formally closed in 2015.
"Our task now is to obtain the necessary cooperation from the countries concerned."
Reports submitted to the UN indicate Mpiranya could be moving around southern Africa.
Brammertz insists Mpiranya is still alive, despite claims to the contrary by some Rwandan exiles.