The International Criminal Court on Monday delivers its verdict against former Congolese vice president Jean-Pierre Bemba, blamed for a campaign of rapes and killings by his private army in the Central African Republic.
It is the first case before the ICC to focus heavily on sexual violence and rape as a war crime and crime against humanity.
A conviction against Bemba on those charges would mark an important milestone in international moves to punish such crimes.
Once a feared rebel leader in the vast north of the Democratic Republic of Congo, Bemba, 53, is accused of failing to halt abuses by his Congolese Liberation Movement (MLC) which he sent into the Central African Republic in October 2002 to help put down an attempted coup against then president Ange-Felix Patasse.
Some 1,500 Bemba troops allegedly went on a rampage of killings, rapes and pillage in villages in DR Congo's northern neighbour from October 2002 to March 2003.
Bemba has pleaded not guilty to three counts of war crimes and two of crimes against humanity at his marathon trial at the ICC which opened in November 2010, after he was captured in Brussels and handed over in 2008. If found guilty, sentencing will be at a later date.
It will only be the fourth verdict -- and the first against a former vice president -- to be handed down by the court, set up in 2002 in The Hague to try the world's worst crimes.
It is also the first case before the ICC to allege that a commander is criminally responsible for abuses carried out by his troops, even if he did not order the violence.
"The upcoming judgement will hopefully provide important clarification on the responsibility of military commanders for the actions of their troops and for their failure to prevent, repress or punish the commission of crimes," Aaron Matta, an expert with the Hague Institute for Global Justice, told AFP.
A guilty verdict could "serve to show that impunity will not go unpunished and that even if it takes a considerable period of time, the ICC can eventually get to the perpetrators," he added.
War crimes prosecutors allege Bemba had authority and control over his troops -- even while across the border -- and could have acted to stop the violence.
- 'Bloody' chain of command -
But Bemba's defence team has insisted he had no command over his troops in the CAR.
"There is not a single documentary piece of evidence that shows any orders passing from Bemba and going to his troops in the Central African Republic," defence lawyer Kate Gibson said in her closing argument.
Numerous witnesses during the trial testified to a series of brutal murders and rapes by MLC soldiers, sent in to prop up Patasse against his arch-foe Francois Bozize.
The first witness described how beret-clad soldiers raped a young girl aged about eight or nine "covered in blood".
"Because the little girl was still... fresh, they did not take the mother, they preferred the little girl (who) they raped in front of her mother," the witness said.
Violence has continued to flare throughout the region. Patasse was ousted by Bozize in 2003 who went on to rule the Central African Republic for a decade, until he in turn was booted out in 2013, sparking a further round of bloodshed.
Matta voiced hopes that a guilty verdict against Bemba could "help improve the security situation and promote peace in the region through deterrence."
After the events in CAR, Bemba, a wealthy businessman-turned-warlord, went on to become one of four vice presidents in President Joseph Kabila's transitional government.
In 2006, he lost in presidential polls against Kabila. He fled the next year into what he called "forced exile" in Europe after his troops were routed by government forces, and was arrested in 2008.
Even if acquitted, Bemba and four close associates are on trial in a second case in which they are accused of bribing witnesses in the main trial.