Most of Rivière's fellow officers naturally assumed that he had been either shot or stabbed to death on the battlefield there and then, but many Vietnamese believed that he had been taken alive by the Black Flags.
Sebagian besar rekan petugas Rivière secara alami beranggapan bahwa ia telah ditembak atau ditikam hingga tewas di medan perang di sana dan kemudian, tetapi banyak orang Vietnam percaya bahwa dia telah ditawan hidup-hidup oleh Bendera Hitam.