A judge who was said to have died of a heart attack while overseeing a corruption trial involving the president's chief of staff in the Democratic Republic of Congo actually died of stab wounds to the head, the justice minister has revealed.
Celestin Tunda Ya Kasende said a murder investigation had now been launched.
In May, police said Judge Raphael Yanyi had died of a heart attack.
He had been presiding over the trial for corruption of Vital Kamerhe.
But an autopsy has since shown "he died a violent death, due to the blows of sharp points or knife-like objects, which were thrust into his head", Justice Minister Celestin Tunda Ya Kasende told Reuters news agency on Tuesday.
Yanyi's body also showed signs of "toxic substances in non-lethal doses", the justice ministry said.
Mr Kamerhe, once a key member of President Felix Tshisekedi's government, is accused of embezzling more than $50m (£39m) of public funds. He denies all accusations of wrongdoing.
His supporters believe the trial is politically motivated - aimed at stopping him from running for president in the future.
Mr Kamerhe is the most high-profile politician to have faced such charges in the country. The trial continued with a replacement judge after Yanyi's death.