He did research, interviewed survivors and traveled through Europe to find scores.
The office conducted an investigation and interviewed survivors of forced labor at the V-2 factory.
He interviewed survivors of the camp who had performed it or heard it.
They were interviewing survivors in their hospital beds.
I spent a couple of hours interviewing survivors and caught an early train back the next morning to New York.
Steidle appears throughout the film, narrating what he witnessed and interviewing survivors in Darfur.
"We're interviewing survivors, witnesses, employees, anybody who was in or around the hotel or who might know something about what went on there," he said.
They interviewed survivors or the family members of those who died.
He spoke to a couple of officers who had interviewed witnesses and survivors.