Listen to RFI's exclusive report with interviews from specialists in Phomn Penh
Forty years after the fall of the Khmer Rouge government, the UN-backed ECCC court convicted two of the movement's former top officials of genocide.
Those convicted were former head of state Khieu Sampan and so-called "Brother No 2" Nuan Chea, now 87 and 92 years old respectively.
The defendants were already convicted in 2014 over the forced evacuation of Phnomh Penh in 1975 and have been serving life sentences since then.
Expensive and lengthy procedure
Since the ECCC court was set up in 2006, there have only been three verdicts, costing up to 265 million euros.
Friday's ruling was symbolic and, in spite of the expense and long years of waiting, the verdict is necessary for the Cambodian people, according to Youk Chhang, a survivor of the Khmer Rouge exactions, who now heads of the Documentation Centre of Cambodia, a resource centre on the Khmer Rouge era.
"Any international trial with the participation of the UN is always expensive," Chang told RFI.
"For surviving victims like myself, there are many things that the ECCC has brought to the understanding and attention of the Cambodian people. We must respect the court and leave it as it is."
Justice and closure for Cambodian youth and religious minorities
An estimated two million people died under Khmer Rouge rule in the late 1970s, accounting for a quarter of Cambodia's population.
Claiming to be communists, regime leaders clamped down on all religious pratice.
Apart from Buddhists, the lesser-known Cham Muslim minority was targeted.
Both Buddhist monks and Cham Muslims went on special buses to attend the hearing and witness the verdict.
Farina So, a history scholar researching Cham Muslims, says that the community was forcibly evacuated from their homes.
She was born after the Khmer Rouge regime fell and represents the young generation.
She grew up listening to her mother tell her about how the Khmer Rouge clamped down on the Muslim community.
"My mother and her family were evacuated to the countryside, where they were forced to eat pork and abandon Islam," she told RFI
The genocide verdict is imporant for young Cambodians, she said.
"This is part of our identity, part of our history," she explained. "This has become the past but it has to be told. That's why it is very important for young people like me to see this kind of justice done."