After a five-year-long war ended in 2003, it was easier for scientists to conduct field research in the Congo. Also recruited by Ammann was Shelly Williams, an experimental psychologist affiliated with "National Geographic" magazine, who claimed to be the first scientist to see the 'Bili apes'. Williams returned to the US with videos, apparently purchased from one of Ammann's long-term trackers. Williams reported on her close encounter, "we could hear them in the trees, about 10 m away, and four suddenly came rushing through the brush towards me. If this had been a mock charge they would have been screaming to intimidate us. These guys were quiet, and they were huge. They were coming in for the kill – but as soon as they saw my face they stopped and disappeared".