Police in Uganda have arrested one of the most wanted suspects from Rwanda's 1994 genocide, Idelphonse Nizeyimana.
Mr Nizeyimana, a former army captain and senior intelligence officer, had entered Uganda from Democratic Republic of Congo on October 1st and was detained in Kampala on Monday, a senior police source said.
He had been extradited to Arusha, northern Tanzania, to the International Criminal Tribunal for Rwanda (ICTR), he said.
A spokesman for the court confirmed the arrest.
Mr Nizeyimana was among the dozen most wanted suspects sought by the UN court over the genocide in which about 800,000 ethnic Tutsis and politically moderate Hutus were killed.
The United States had offered a $5-million reward for his capture. He is charged by the ICTR with genocide, complicity in genocide, and direct and public incitement to commit genocide.
The tribunal says Mr Nizeyimana and others prepared lists of Tutsi intellectuals and those in authority before handing the lists to troops and militia who then killed them.
He is also accused of setting up roadblocks where Tutsis were slaughtered, and of providing weapons and transport to militia in the knowledge they were being used for attacks.
Rwanda's government, which says Mr Nizeyimana was the main organiser of the genocide in the southern province of Butare, says he has spent the 15 years since the slaughter fighting for a Hutu rebel group in the forests of neighbouring eastern Congo.
"In Kinyarwanda his name would translate as 'I believe in God,' which unfortunately is not the case. He believes in death," said Rwandan justice minister Tharcisse Karugarama.
"He was an agitator, a handler, the chief killer in Butare," Karugarama told Reuters by telephone. "The arrest of this man ... is a very big relief to survivors of the genocide."
It was the second big arrest in about two months.
Gregoire Ndahimana, a local administrator in Rwanda during the genocide, was caught in August by Congolese troops during UN-backed operations against Hutu rebels from the Democratic Forces for the Liberation of Rwanda.
He was transferred to the ICTR in Tanzania last month.
Reuters