[JURIST] The trial chamber of the Extraordinary Chambers in the Courts of Cambodia (ECCC) [official website] ruled [press release] Thursday that the sister-in-law of former Khmer Rouge leader Pol Pot [BBC backgrounders] is not mentally competent to stand trial, ordering her release. The tribunal held that Ieng Thirith [ECCC profile], the so-called “First Lady” of the Khmer Rouge, is mentally incompetent to face trial after court-appointed medical experts testified that she is probably suffering from Alzheimer’s disease:

[T]he Trial Chamber has today reaffirmed its prior finding that the Accused Ieng Thirirth suffers from a progressive, degenerative illness (likely Alzheimer’s disease) and that she remains unfit to stand trial. The experts have confirmed that all treatment options have now been exhausted and that the Accused’s cognitive impairment is likely irreversible. As there is no prospect that the Accused can be tried in the foreseeable future, the Trial Chamber has confirmed the severance of the charges against the Accused Ieng Thirith…and indefinitely stayed proceedings against her.

Ieng Thirith has denied responsibility for any crimes committed by the Khmer Rouge during its four-year reign in the 1970s.

Last week, the ECCC announced [JURIST report] that it would declassify more than 1,700 war crimes documents. The ECCC has only convicted one former Khmer Rouge leader, Kaing Guek Eav [case materials; JURIST news archive]. Ieng Thirith was indicted [JURIST report] in September 2010 along with Ieng Sary, Khieu Samphan and Nuon Chea. The ECCC ruled in November that Ieng Thirith was unfit to stand trial [JURIST report], but the Supreme Court Chamber ordered that she remain in detention [JURIST reports] and that the Trial Chamber exhaust all measures so that she can stand trial. The other three went on trial [JURIST report] in November. In July the ECCC appointed a new judge to prosecute two new war crimes cases [JURIST report].