PARIS — He was behind the radio station whose hate-filled invectives turned Rwandan against Rwandan, neighbor against neighbor, even spouse against spouse. He was the man, it was said, who imported the hundreds of thousands of machetes that allowed countless ordinary people to act upon that hatred in one of the last genocides of the past century.
One of the most-wanted fugitives of the 1994 Rwandan genocide, Félicien Kabuga, was arrested Saturday morning in a rented home just outside Paris, protected by his children, the French authorities said. The capture of Mr. Kabuga, 84, who was living under a false identity, was the culmination of a decades-long international hunt across many countries on at least two continents.
His arrest — considered the most important apprehension by an international tribunal in the past decade — could help bring long-awaited justice for his actions more than a generation after the killing of at least 800,000 and perhaps as many as one million ethnic Tutsis and moderate Hutus in the small central African nation.
His trial could also help unravel some of the enduring mysteries of the killings, particularly how much planning went into the genocide, which also led to a catastrophic war in the neighboring Democratic Republic of Congo and continues to destabilize much of central Africa today.
Mr. Kabuga, one of Rwanda’s richest men before the genocide, is accused by the International Criminal Tribunal for Rwanda of being the main financier and logistical backer of the political and militia groups that committed the genocide. He had been on the run for 23 years since he was indicted on multiple charges of genocide.
“It is historical on many levels,” Rwandan’s justice minister, Johnston Busingye, said in a phone interview from the country’s capital, Kigali. “You can run, but you cannot hide. It can’t be forever.”
A tribunal official said on Saturday that Mr. Kabuga had been tracked down in France after investigators followed communications among members of his family who, the official said, had acted as his support network.
It was not known how and when Mr. Kabuga entered France, and how he had managed to evade detection while living in Asnières-sur-Seine, a well-off suburb just northwest of Paris.
He was arrested at his home around 7 a.m. after a long investigation by French national police specializing in crimes against humanity, with help from the federal police in Belgium and the Metropolitan Police in London, according to France’s justice ministry.
Mr. Kabuga was expected to be handed over to United Nations prosecutors, with his trial expected to take place in the tribunal’s successor court in Arusha, Tanzania.
“Kabuga has always been seen by the victims and survivors as one of the leading figures,” Serge Brammertz, the chief prosecutor at the tribunal, said by phone on Saturday from The Hague. “For them, after waiting so many years, his arrest is an important step toward justice.”
Mr. Kabuga’s capture could be the most important arrest of a figure wanted by an international tribunal since the 2011 apprehension of Gen. Ratko Mladic, the Serbian military leader who was later convicted of having committed genocide during the Bosnian war of the early 1990s, Mr. Brammertz said.
The arrest ended a lengthy and often-frustrating search for Mr. Kabuga by international investigators across multiple countries.
Stephen Rapp, a former chief prosecutor at the United Nations Rwanda tribunal, said that immediately after the genocide Mr. Kabuga fled to Switzerland, where he unsuccessfully applied for asylum, and was then seen in other European countries before settling in Kenya for several years. Mr. Rapp said the fugitive had used assumed names and several different passports.
In 2002, the United States government began circulating wanted posters in Nairobi, the Kenyan capital, one of his known hide-outs. In an attempt to use its own resources and official connections to catch him, the United States had offered a reward of up to $5 million for his capture.
But with his huge bank account and high-level connections, Mr. Kabuga had managed until Saturday to escape an arrest warrant issued by the tribunal in 1997.
In the late 1990s, Mr. Kabuga was traced to a house owned by Hosea Kiplagat, a nephew of Kenya’s president at the time, Daniel arap Moi of Kenya, according to a report published in 2001 by the International Crisis Group, a research organization. The study also detailed how investigators for the International Criminal Tribunal uncovered evidence that a Kenyan police officer might have tipped off Mr. Kabuga in 1997 that an arrest was imminent.
The Kenyan government at the time disputed the allegations that it had not been diligent in its search for Mr. Kabuga.
In 2001, the United Nations court froze bank accounts that Mr. Kabuga held or had access to in Switzerland, France, Belgium and Germany.
Believed to have been one the most powerful men in Rwanda before the genocide, Mr. Kabuga, an ethnic Hutu, made his fortune in trade. Through the marriage of a daughter, he was linked to a former president, Juvénal Habyarimana, a Hutu, who was killed after his plane was shot down by a missile over the Rwandan capital in 1994.
Extremist Hutus accused Tutsis of carrying out the assassination, eventually triggering 100 days of killings in which tens of thousands of Rwandans, including civilians, militia and the police, participated.
The Rwandan government has tried thousands of people, and the United Nations Criminal Tribunal for Rwanda has tried close to 80, among them senior government figures. After Mr. Kabuga’s capture, at least six senior figures suspected of participating in or orchestrating the genocide remain on an international most wanted list.
Mr. Kabuga was charged with using his fortune to fund and organize the notorious Interahamwe militia, which carried out the brunt of the slaughter, often carried out by hacking people to death.
He is accused of issuing them weapons, including several hundred thousand machetes imported from China, which were shipped to his companies, as well as providing them transport in his company’s vehicles.
The indictment against him also alleges that his radio station, Radio-Television Mille Collines, incited the killings through broadcasts that directed roaming gangs of killers to roadblocks and sites where Tutsi could be located.
“His trial may help us understand to what extent the genocide was planned,’’ said Filip Reyntjens, a Belgian expert on the genocide. “Kabuga is often mentioned as someone who was involved through the funding of the extremist radio station. He’s also mentioned in the context of the purchase of machetes. All of that will need to be proven, but a trial could unearth of a lot of things 26 years after the genocide.’’