( CNN ) -- Lawyers for a man who ran a notorious torture prison in Cambodia where more than 14,000 people died during the 1970s Khmer Rouge regime are appealing his conviction . The lawyers for Kaing Guek Eav , alias Duch , say he should be acquitted since he was `` a witness of the events of the relevant period '' and should be in witness protection -- not detention . Duch was convicted of war crimes , crimes against humanity , murder and torture in July in a U.N.-backed war crimes tribunal also known as the Extraordinary Chambers in the Courts of Cambodia . Duch 's lawyers also say the court did not have jurisdiction , the appeal states . `` To interpret the applicable law in reliance on international customary law is inconsistent '' with the law of the Extraordinary Chambers in the Courts of Cambodia , according to the appeal . Earlier this month , prosecutors in Cambodia appealed Duch 's 30-year sentence , saying the punishment was too light . `` The co-prosecutors are of the view that the judgment gives insufficient weight to the gravity of Duch 's crimes and his role and his willing participation in those crimes , '' they said in a statement . `` At the same time , the co-prosecutors believe that undue weight is placed on any mitigating circumstances applicable to Duch . '' Some survivors had been angered by the sentence for Duch . His prison term would have been about 19 years after the court took off 11 years for the time he has already served behind bars . The verdict sparked strong reactions as word spread outside the courtroom . Some said it made them lose faith in the U.N.-backed war crimes tribunal . `` It 's becoming a sham , '' Cambodian-American Theary Seng , chairwoman of the Center for Justice and Reconciliation , said after the verdict . At least 1.7 million people -- nearly a quarter of Cambodia 's population -- died under the 1975-1979 Khmer Rouge regime from execution , disease , starvation and overwork , according to the Documentation Center of Cambodia . Duch , 67 , was the head of the S-21 prison . Few people brought to the prison made it out alive ; only about a dozen were found by the Vietnamese , who invaded Cambodia in 1979 . Prosecutors had initially sought a 40-year sentence . The judges first gave Duch 35 years , but took five years off that for the time he was illegally detained before the tribunal was established . Prosecutors have said the judgment failed `` to reflect the full extent of Duch 's criminal conduct '' and he should be `` separately convicted of the crimes against humanity of enslavement , imprisonment , torture , rape , extermination , and other inhumane acts . These crimes should not have been subsumed into the crimes of persecution and torture . '' The judge , in announcing Duch 's sentence , said he took into consideration that the defendant had expressed remorse , admitted responsibility and cooperated with the court . The judge also took into account the `` coercive environment '' of the Khmer Rouge , he said . Duch pleaded guilty , but he said he was only following orders and asked for forgiveness . Last November , he asked to be freed after spending some 11 years in detention . In the last week of his trial , Duch argued that international law did not apply to him because he was following orders . The tribunal began its work in 2007 after a decade of on-and-off negotiations between the United Nations and Cambodia over the structure and functioning of the court . Duch 's verdict was the court 's first . Another four of the ultra-Maoist regime 's former leaders are waiting to see if they will stand trial before the U.N.-backed tribunal for war crimes and crimes against humanity . Co-prosecutors filed a final submission in these cases and asked that the four be indicted and sent for trial , according to a statement from the prosecutors ' office . It 's not known when the court will make a decision .
Attorneys : Duch was `` a witness of the events '' and should be in witness protection . Duch is convicted of war crimes , crimes against humanity , murder and torture . Prosecutors : 30-year sentence is too light .