Up to two million people, a lot of them ethnic Khmer, are believed to have died under the brief but systematically brutal Khmer Rouge regime between 1975 and 1979.
On November 16, 2018, the two are sentenced to life in prison on charges of genocide.
He and Nuon Chea were already serving life sentences for crimes against humanity and the additional life sentence will be served concurrently.
A man cleans a skull near a mass grave at the Chaung Ek torture camp run by the Khmer Rouge in this undated photo.
Between 1.7 and 2.2 million people, nearly a quarter of the population, died during the 1975 to 1979 rule of the Khmer Rouge.
They were also sentenced to life imprisonment for crimes against humanity, including murder, extermination, deportation, enslavement, imprisonment, torture, religious and racial persecution, disappearances and rape. Families of victims say it has been a long and tough battle for justice but many feel punishing leaders of the regime still alive would be a deterrent against any similar regime which may crop up here or anywhere else.
The court found Khieu Samphan not guilty of genocide against the Cham, for lack of evidence, though he was found guilty of genocide against the Vietnamese under the principle of joint command responsibility.
The Khmer Rouge seized power in 1975 after a bloody five-year civil war.
Prime Minister Hun Sen, himself a former Khmer Rouge guerrilla who defected to the regime's eventual conquerors, Vietnam, said he would "not allow" any new indictments beyond the handful of top leaders.
Khieu Samphan described the claim of genocide as "Vietnamese propaganda", a defence he and other former Khmer Rouge leaders have made previously.
The UN tribunal, officially called the Extraordinary Chambers in the Courts of Cambodia, was established in 1997, but has been hindered by the deteriorating health of defendants and political interference.
Khieu Samphan had at one point been the smiling, polite figurehead who nominally was the head of state in the Khmer Rouge regime. Khieu Samphan denied knowing about matters including forced marriages and violent oppression of minorities, and both men mounted political defences.
Khieu Samphan, left, former Khmer Rouge head of state, stands at the dock in a court room during a hearing at the United Nations -backed war crimes tribunal in Phnom Penh, Cambodia, on Friday.
Nuon Chea, 92, was brought by ambulance and Khieu Samphan by van from the nearby prison where they are held. "Last night, I could not sleep because I was afraid that Nuon Chea and Khieu Samphan could die before this verdict was announced".
The ground rules under which the tribunal was established in 2005 are complicated, providing for hybrid courts pairing Cambodian judges and prosecutors with global counterparts.
Established in 2006 with both Cambodian and worldwide judges, it has so far only convicted three people for the atrocities of the Khmer Rouge regime at a cost of $300m (£232m). "They will always be political and fall short of expectations", said Alexander Hinton, an anthropology professor at Rutgers University and author of two books about the tribunal.
Since this is an all-new Corolla and not a facelift, the question isn't so much if we're going to get it here, but rather when. Toyota Turkey launched its first hybrid vehicle, C-HR - a sport utility vehicle (SUV) - in October 2016 in Turkey.
Kevin McCarthy and Federal Emergency Management Agency chief Brock Long, the president shook hands with greeters on the tarmac. "I pay tribute to the courage and dedication of the US emergency services and the volunteers that have provided support".
The ATP Cup, which will offer $15 million in prize money for players, will be held in partnership with Tennis Australia. The "ATP Cup" will kickstart the year on January 3 of that year in three Australian host cities, yet to be decided.
Similarly, the 12.9-inch model starts at INR 89,900 for the base model, with the top-of-the-line model costing INR 1,57,900. Face ID brings support for Animoji and Memoji, and it works in both portrait and landscape mode, unlike the iPhone models.
The Democratic candidate for Florida governor, Andrew Gillum , conceded the race to Republican Ron DeSantis , again, on Saturday. Snipes has already been under fire for the way her office has handled the election and recount.
It only delayed the inevitable, though, as Anderson duly served out for a 6-0 6-1 victory in 63 hopelessly one-sided minutes. It was a landmark moment for Wimbledon finalist Anderson, who has set a new career-high of 47 victories in a calendar year.
But while " toxic " may be a bit of a downer for word of the year, at least the runner-ups didn't take the crown. Oxford Dictionary's Word of the Year in 2017 was " youthquake " while "post-truth" topped the list in 2016.
Microsoft's next-gen "Scarlett" consoles reportedly won't be released until 2020, according to various reports . That's an attractive price point for a new Xbox One, especially if you don't care about physical games.
It does not mean the body is becoming resistant to antibiotics; it means bacteria mutate and antibiotics are no longer effective. However, antibiotics are often used when they should not, which can cause them to stop working.
Watch Elton John's Reputed $6.5 Million Commercial
However, as you'll read below, not everyone's a fan of the spot, with some complaining the ad simply isn't Christmassy enough. Elton's famous hit " Your Song " is the song for this years ad which is also called "The Boy and The Piano".
MEASUREMENT OVERHAUL: New definition for kilogram approved
The metric system - or, as it is known today, the International System of Units (SI) - is an unbelievable achievement of mankind. In 2013, scientists discovered that the kilogram Prototype had gained tens of micrograms of mass from surface contamination.
FCC Lets Elon Musk's SpaceX Deploy Over 7000 Satellites
Our approach to these applications reflects this commission's fundamental approach to encourage the private sector to invest. The FCC also approved access to the US market for satellites from Kepler Communications Inc., Telesat Canada and LeoSat MA.
The hunt is on for Black Friday savings
Below we've put together a list of some of the best deals available now, plus those that won't start until Black Friday. The promo starts November 16 and will run through Black Friday on November 23.
One killed and 47 injured in France fuel tax protests
But up to 200 people were later seen walking down the street, apparently heading toward the Elysee presidential palace. Many drivers see them as emblematic of a presidency disconnected from day-to-day economic difficulties.
New Study Claims that Social Media Makes us Lonelier
They then collected objective usage data automatically tracked by iPhones for active apps , not those running the background. Young said the Penn study was unique due to its more conclusive relationship between social media and negative effects.