Phnom Penh, Cambodia (CNN) -- A man who ran a notorious torture prison where more than 14,000 people died during the Khmer Rouge regime was found guilty of war crimes Monday and sentenced to 35 years in prison -- with 5 years taken off that sentence for time served.
The verdict against Kaing Guek Eav, alias Duch, also convicted him of crimes against humanity, murder and torture.
It was a historic first for a U.N.-backed war crimes tribunal.
Duch, 67, was the head of the S-21 prison, where at least 14,000 people died.
"It's clear that he will never be a free man again," said Youk Chhang, director of Documentation Center of Cambodia.
Prosecutors had asked for a 45-year sentence with 5 years' credit for time served.
Duch pleaded guilty, but said he was only following orders and asked for forgiveness.
In the last week of the trial, he argued that international law did not apply to him because he was following orders.