The man who ran the Khmer Rouge regime’s “factory of death” will spend the rest of his life behind bars.

Kaing Guek Eav, alias Duch, prison chief at the notorious S-21 detention facility, had his prison sentence increased to life in an appeal ruling today by the Khmer Rouge tribunal’s highest judiciary chamber.

“In the Supreme Court Chamber’s view, [Duch’s] leadership role and particular enthusiasm in the commission of his crimes are aggravating factors that should be given significant weight in the determination of his sentence,” Supreme Court Chamber president Kong Srim read from a summary of the judgment yesterday, adding that the “particularly shocking and heinous character” of his crimes over an “extended period of time … undoubtedly place this case among the gravest before international criminal tribunals.”

Duch had originally been sentenced to 35 years in prison by the Trial Chamber, of which he was slated to serve about 19 years behind bars.

However, the Supreme Court Chamber today said that undue weight had been given to mitigating factors, such as Duch’s expressions of remorse and cooperation, and replaced the penalty with a life sentence.

The Chamber ruled that Duch has served 12 years and 269 days of his sentence so far, including time he was illegally detained by the Cambodian Military Court from May 1999, as his detention there was for “broadly similar” reasons as his ultimate conviction.

Civil parties who appealed the Trial Chamber’s decision will be disappointed with the Supreme Court Chamber’s decision to not grant any additional reparations requests. The Chamber adopted in full the Trial Chamber’s decision on reparations.

Duch, who was present in the docks, listened attentively to the pronouncement of the Supreme Court Chamber, and bowed his head, raising both hands in a prayer at the conclusion of the judges’ statement.

The pronouncement of the appeal decision in Duch’s case signals the conclusion of the tribunal’s landmark first case.