A former ally of Rwandan President Paul Kagame has accused him of complicity in the death of a former president which sparked the 1994 genocide.
Theogene Rudasingwa said he heard Kagame boast in 1994 that he ordered the shooting down of the plane carrying President Juvenal Habyarimana.
"By committing that kind of crime Kagame has the responsibility in the crime of genocide," he told the BBC.
President Kagame has repeatedly denied any involvement in the attack.
Rudasingwa, who lives in the US, has fallen out with Kagame in recent years and was sentenced in absentia in March to a 24-year jail term for threatening state security and propagating ethnic divisions.
Anchor Marco Werman talks to the BBC's Mark Doyle about this explosive allegation.