An Argentine former pilot, who is suspected of helping kill opponents during the country's military junta, faced Dutch prosecution witnesses via video link from Buenos Aires on Wednesday.
Julio Poch, who holds Dutch citizenship now, was extradited to Argentina in 2010 for allegedly flying planes that carried hundreds of dissidents that were later drugged and thrown out of the planes in mid-air during Argentina's 1976-1983 "dirty war."
The 62-year-old Poch is on trial in Buenos Aires where the court has requested that the Dutch pilots be questioned by video link.
On Wednesday, the first two pilots are expected to sit in a courtroom in Rotterdam to be questioned by the Argentine prosecutor, judges and Poch himself.
Two others will follow a week later.
Poch has requested a further six witnesses be heard from Rotterdam, this time for the defence.
Poch denies involvement in the so called "death flights" during the country's military regime, but allegedly told a number of pilots at Dutch airline Transavia (air charter company), where he worked between 1988 and 2010, that he was involved in those flights.