The former chief interrogator and torturer for Cambodia's Khmer Rouge has been discharged from hospital after a health scare that lasted weeks, an official told AFP Tuesday.
Kaing Guek Eav, better known as Duch, is serving a life sentence for managing the Phnom Penh detention centre S-21 where some 15,000 people were confined and sent to their deaths in nearby "Killing Fields" in the late 1970s.
The former mathematics teacher-turned-diehard revolutionary was the first member of the Khmer Rouge to face judgement before a war crimes tribunal in Cambodia and was sent to live out his remaining days in Kandal prison after an appeal extended his original sentence to life in 2012.
Duch fell ill with respiratory problems in late October and was rushed to hospital in the capital Phnom Penh where his condition was deemed serious at the time, but the head of the prison said he pulled through.
"I did not hope he would survive," Chat Sineang, director of the Kandal prison, told AFP.
"But he has recovered from the illness and he arrived back at the prison on Monday evening."
He said, however, that Duch -- who turns 76 in a few days -- was still weak and needed help from guards when he wanted to use the bathroom.
Duch was arrested in 1999 after being discovered working for a Christian aid agency under a false name.
His trial was a landmark for victims seeking justice for crimes under the Khmer Rouge regime, whose dreams of an communist agrarian paradise led to the deaths of up to two million Cambodians from 1975 to 1979.
Though Duch asked for forgiveness, he also argued that he was not a senior leader of the ultra-Maoist movement and should therefore be acquitted.
But S-21 was at the heart of the Khmer Rouge's fearsome security apparatus and many inmates were tortured into signing false confessions of wrongdoing.
The UN-backed trial in Phnom Penh has been tainted by its limited scope and the age of its defendants since it started more than a decade ago, recording only three convictions -- including Duch's.
Ieng Thirith, the Khmer Rouge social affairs minister and one of the suspects on trial in the case after Duch's, was released on mental health grounds before dying in 2015.
Her husband and co-defendant Ieng Sary died two years earlier.