PHNOM PENH, Cambodia, Sept. 17 (UPI) --

The second in command of Cambodia's deadly Khmer Rouge regime during the 1970s will stand trial next year charged with genocide, torture and religious persecution.
In the dock will be Nuon Chea, who, as deputy to Khmer Rouge leader Pol Pot, was the second most powerful person in the regime that lasted from 1975-79.
An estimated 1.7 million Cambodians -- one-fifth of the population -- lost their lives under the regime, which was overthrown by an invading army from neighboring Vietnam in 1979. Hundreds of thousands of Cambodians fled the country into exile and uncertain refugee status.
The Khmer Rouge abolished religion, schools and currency to create an agrarian utopia through forced migration from the cities into the countryside. But most are believed to have died of starvation, overwork or were executed by government officials and the military.
Chea, 84, will be joined by three other senior Khmer Rouge leaders, all indicted by Cambodia's U.N.-backed war crimes tribunal. Facing the same charges are former head of state Khieu Samphan, former Foreign Minister Ieng Sary and his wife Ieng Thirith, who was the regime's social action minister.
Chea is believed to have been a key architect of the regime's mass killing strategy. He has acknowledged that deaths took place but denies he had any authority to stop them.
Ieng Sary, 84, was the former minister of foreign affairs. He was found guilty of genocide in a Vietnamese-backed trial of former leaders in 1979.
Ieng Thirith, 78, studied English literature in Paris and was Pol Pot's sister-in-law.
Khieu Samphan, 79 and also French-educated, was one of the regime's few diplomats who had contact with the outside world because he was officially head of state.
There were fears that the trial, expected to be one of the most complicated genocide trials, wouldn't happen.
The four Khmer Rouge leaders were arrested in 2007 and have consistently denied the charges that include torture, rape and murder. The tribunal judges were facing a Sept. 19 deadline to hand down indictments or release them.
The court has decided to "send forward these four accused for trial," Judge You Bunleng said at a news conference.
The trial of the four leaders is the second such trial for the country that still feels the pain of what became known as the "killing fields" because of huge number of deaths and subsequent unearthing of mass graves.
Many families remain traumatized and also in the dark about what happened to their kin and friends after they were forcibly removed to the countryside.
In July the 67-year-old math teacher, Christian convert and Khmer Rouge cadre Kaing Guek Eav was given a 35-year jail sentence for crimes against humanity committed during the regime. It was the court's first guilty verdict against a senior Khmer Rouge party figure.
Eav, commonly known as comrade Duch, was director of the notorious prison and feared interrogation center Tuol Sleng, or S-21, in the capital.
An estimated 16,000 men, women and children were systematically tortured, many beaten to death, at the prison. Cambodian officials say only 14 people survived Tuol Sleng. In particular, Duch is alleged to have ordered the executions of 160 children in a single day.
Judges at the trial of Duch, who is the only one to have shown remorse, reduced his sentence by five years after ruling that he had been illegally detained by a military court following his arrest in 1999. Another 11 years were loped off the sentence because of time served in jail awaiting his trial, meaning he faces 19 years in prison.
Despite his stated remorse, Duch always contended that he was simply carrying out orders from his superiors and did so because he feared for his own life.
The top leader, Pol Pot, fled the country after the Vietnamese invaded in 1979 and he died in 1998.