The most brutal killings happened at S-21/Tuol Sleng Prison in the capital.
S-21 was a high school turned into a torture chamber.

16,000 people went in… their faces each documented upon entry…

Twelve survived.
…
After multiple rounds of brutal interrogations, the prisoners were blindfolded and driven to Choeung Ek–also known as the killing field.
…
…
I spent two days walking around S-21 and Choeung Ek.
Nothing in my life could have prepared me to walk down paths mottled with bones and clothing mixed in the dirt between the mass graves.
Nothing.
…
…
I still cannot put into words the thoughts that ran through my head when I stared up a five story tower of skulls piled on top of skulls. 
…One man was in charge of this prison…
He was a young math teacher when he first joined the Khmer Rouge…
He carefully documented and gave the orders to carry out the execution of 16,000 people– men, women, children, babies…

I saw him when I went to Cambodia two years ago.
Thirty years after the genocide, the UN set up a tribunal to bring truth and to prosecute the few who were still alive–really, just one (as Pol Pot and two others are dead, and the other two have diplomatic immunity overseas and live in Hawaii).
…
The one who has stood trial on behalf of everyone is a small man named Duch.
Duch has been imprisoned by the people of Cambodia since 1993. He did not stand trial until 2009.
During his sixteen year stay in prison, Duch came to know Christ as His Savior.
And he professed it in the UN Tribunals while I was there.
He said that his faith in Buddhism would never set him free for the things he most regrets in his life.
He said that there is only one God who forgave Him–the true God who sent His only son to die for Duch’s sins…
…and his sins have faces…
The man I saw on trial was soft, was full of life, full of conviction, and the only man who was being honest in the entire trial process. He was surrounded by corrupt officials, even more corrupt lawyers, the most corrupt of all–the judges.
…The trial was a sham…
His guilt is well known, well-documented, well-circulated.
But still, this man knows that someone died for him.
There is grace to cover this one man who is responsible for the death of thousands of people.
This man is LOVED by the I Am.
This man is COVERED by the GRACE of the Creator of All.
This man is bringing HOPE to a country that he once set out to destroy.
That’s the power of my God’s redemption.
