Rights groups have welcomed the arrest in Belgium of a female commander of Charles Taylor's rebel group for war crimes allegedly committed during Liberia's civil war.
The arrest follows a complaint filed on behalf of three victims of an offensive in 1992 known as Operation Octopus.
Martina Johnson has not yet responded to accusations of involvement in "mutilation and massing killing".
Taylor has been jailed for war crimes committed in neighbouring Sierra Leone.
A special UN-backed court found him guilty in 2012 of supplying weapons to the Sierra Leonean rebels in exchange for so-called blood diamonds.
He launched a rebellion in Liberia in 1989, becoming president in 1997 - but he was forced into exile by another rebel offensive in 2003.
'Hope for justice'
Civitas Maxima, a Geneva-based legal advocacy organisation which helped bring the case against Ms Johnson, said since the end of Liberia's civil war in 2003, no effort has been made by the authorities to investigate and prosecute crimes committed during Liberia's conflict.
This is despite a recommendation in 2009 of the Liberian Truth and Reconciliation Commission to do so.
The group has working with Liberian non-government organisation Global Justice and Research Project (GJRP) to document the alleged crimes.
"We believe that this will begin to give people hope in Liberia for justice," GJRP's Hassan Bility told the BBC's Focus on Africa radio programme.
"You can never build a true democracy if you do not have justice as one of its cardinal foundations."
Ms Johnson, who was arrested on Wednesday in Gent, is due to appear on court on Friday to decide if she will remain in detention during legal proceedings.
US-based Human Rights Watch said her arrest was a "major advance for justice".
She is accused of participating directly in the National Patriotic Front's Operation Octopus, in which many civilians were brutally killed because they were members of ethnic groups, such as the Mandingos and the Krahns, Civitas Maxima said in a statement.
The Small Boys Unit, made up of child soldiers, took part in the assault - and was one of the rebels' most feared battalions.
Belgium's universal jurisdiction law allows the country's judges to prosecute human rights offences committed anywhere in the world.