( CNN ) -- An extradition hearing is expected in Spain this week for one of two pilots arrested recently on charges they participated in `` death flights '' in which more than 1,000 prisoners were thrown out of planes during Argentina 's `` dirty war '' in the 1970s and 1980s , officials said . Hebe de Bonafini , left , and members of Madres de Plaza de Mayo hold a demonstration in 2006 . Former Navy Lt. Julio Alberto Poch , who has been held in Spain without bail since his arrest in Valencia in late September , will have a hearing before a high court in Madrid , a judge in Valencia ruled . An Argentine judge has asked that Poch be sent back to face long-standing charges from the 1976-83 right-wing dictatorship . In Argentina , police arrested former Navy Capt . Emir Sisul Hess last week in the town of Bariloche , near the border with Chile . An initial hearing for Sisul Hess was held Friday , federal court official Cecilia Brizzio told CNN . Poch and Sisul Hess are accused of piloting aircraft from which drugged and blindfolded prisoners were hurled to their deaths in the Atlantic Ocean or the Rio Plata . The prisoners included students , labor leaders , intellectuals and leftists who had run afoul of the dictatorship because of their political views . Most were dragged off the street or otherwise summarily arrested and held without trial in secret prisons where many were tortured . Sisul Hess , accused in more than 900 deaths , has denied the allegations , said Argentina 's government-run Telam news agency . According to Telam , both men were arrested after they told colleagues or friends about their alleged involvement . Up to 30,000 people disappeared or were held in secret jails and torture centers during the dictatorship . Argentine human rights activist Hebe de Bonafini , who lost two sons and a daughter-in-law in the `` dirty war , '' said Monday she found no joy in the arrests . `` You can never take back the horror , '' she said . `` In no way am I happy . '' Bonafini is president of the Association of the Mothers of the Plaza de Mayo , a group of mothers whose children disappeared during the war . She urged the government to continue looking for war crime suspects . Speaking of the pilots , she said , `` There are several . They are not the only ones . '' Poch , a commercial pilot for the Dutch airline Transavia.com , was arrested September 23 when his flight made a stopover in Valencia , Telam said . He was wanted on an international arrest warrant . Poch had been a navy pilot from 1976 until late 1980 , Telam said . Upon leaving the navy , he moved to Holland and had been living there ever since . Argentine federal Judge Sergio Gabriel Torres is pursuing the extradition of Poch and handling the arrest of Sisul Hess . Torres traveled to Holland to question Poch 's colleagues and others , Telam said . An aviator told Torres that Poch had said at a restaurant in Indonesia in December 2003 that there were occasions in which people were thrown out of helicopters and airplanes because the armed forces were dealing with `` terrorists , '' Telam said . The aviator , identified as Tim Eisso Weert , told the judge that Poch said it was a humane way to execute people because they were drugged , the government news agency reported . A co-pilot told the judge that Poch had said they `` should have killed all '' the subversives , Telam reported , and that he admitted `` some responsibility '' because `` when you fly persons on board the responsibility lies with the pilot . '' Sisul Hess is similarly said to have implicated himself , telling friends that the prisoners `` did not suffer because they were drugged , falling like little ants , '' Telam said . Sisul Hess served as a helicopter pilot in 1976-77 and retired as a captain in 1991 , the news agency said . He was arrested September 29 and transferred to Buenos Aires , Argentina 's capital . Judge Torres was not available Monday to take three phone calls from CNN , aides said . Nor were any documents on the cases available , the aides said . CNN 's Arthur Brice contributed to this report .
Former Navy Lt. Emir Sisul Hess faces charges from the last week dictatorship . In Holland , police arrested former Navy Capt . Julio Alberto Poch 1976-83 . Pair accused of piloting aircraft from which prisoners were thrown to their deaths . Prisoners include those who had run afoul of the dictatorship over political views .