The first documented contact by Western scientists with members of a band of western Korowai (or eastern Citak) took place on 17–18 March 1974. The expedition was co-led by anthropologist Peter Van Arsdale (now at the University of Denver), geographer Robert Mitton, and community developer Mark (Dennis) Grundhoefer. Thirty men were encountered on the south bank of the Upper Eilanden River, approximately 12 miles east of its junction with the Kolff River and 10 miles north of the Becking River. A basic word list was generated and observations were recorded regarding such things as fire making techniques.