Judges at International Criminal Court are due to give their verdict at the war crimes trial of Congolese militia leader Germain Katanga.
He is accused of being behind the 2003 massacre of more than 200 villagers in the gold-rich Ituri province of north-eastern Democratic Republic of Congo.
Other charges include sexual slavery, rape and enlisting child soldiers.
Mr Katanga, who was transferred to The Hague by the Congolese authorities in 2007, denies the allegations.
The fighting in Ituri, which broke out in 1999 and continued until 2003, started as a struggle for control of land and resources.
But it escalated into inter-ethnic war, exacerbated by the presence of Uganda troops, that killed an estimated 50,000 people.
The charges against Mr Katanga all relate to an attack on Bogoro that took place on 24 February 2003.
ICC prosecutors at The Hague say the assault was designed to “wipe out” the entire strategically important village, which is close to the Ugandan border.
According to the prosecution, the attack happened in the early hours of the morning and some villagers were shot while they slept, while others were cut up with machetes to save bullets.
At the time Mr Katanga was 24 years old and the alleged commander of the Patriotic Resistance Force of Ituri, which had the support of the Lendu ethnic group.
The prosecution say as the FRPI’s leader he was to blame for the atrocities committed by his fighters against the villagers from the Hema ethnic group.
It is also alleged that the women who survived the massacre were raped or kept as sex slaves.
Another person was charged by the ICC in connection with Bogoro attack.
But in December 2012 Mathieu Ngudjolo Chui was acquitted as judges found there was insufficient evidence to show that he was the commander of National Integrationist Front, which also took part in the raid.
The BBC’s Maud Jullien in DR Congo says Mr Katanga was known to his men as “Simba”, meaning lion.
Those who knew him describe him as a discreet man but ruthless on the battlefield, she says.
After the end of the Ituri conflict, peace deals were signed and Mr Katanga was given a position in the Congolese army.
But a year after joining the military he was imprisoned for bad behaviour and was still in prison when the ICC issued its arrest warrant for him.
His is one of the longest-running cases at the ICC.
In July 2012, Thomas Lubanga, who was also a militia leader in Ituri, was sentenced to 14 years in jail by the ICC for recruiting and using child soldiers.