As the Japanese Army advanced into Peking in 1937, many of the scientists at PUMC seriously worried about the fate of the fossils. They learned that the Japanese were actively pursuing the artifacts and had even visited the excavation site looking for evidence of their whereabouts. To protect the fossils from being pillaged, they were temporarily secured in a Peking bank vault.
However, Weidenreich did not believe that the Japanese posed a real threat to the fossils or the ongoing research. He appealed to the Rockefeller Foundation to continue with the excavation at Chou Kou Tien, yet, he was refused. According to Noel Boaz and Russell Ciochons book, Dragon Bone Hill, the hominid fossils were eventually returned to PUMC and no action was taken to safeguard them for the four long years of Japanese occupation.
As tensions increased in 1941, Weidenreich realized that the risk of the Japanese taking the fossils was greater than he initially thought. He expressed his concerns to the president of PUMC, Dr. Henry Houghton, and brought up the possibility of shipping the artifacts to America for safekeeping. However, Houghton feared that the fossils would be destroyed during shipping and decided that it was best for them to remain at the college.
Weidenreich argued with Houghton to reconsider, but he refused to change his opinion. Boaz and Ciochon suggested that Houghton became irritated with Weidenreich and sent him back to America. Before he left, Weidenreich had plaster casts of the fossils made, which he took with him along with his papers so that he could complete his study abroad.
Entrance of PUMC where fossils were kept
In September of that year, a decision was finally made to have the hominid fossils temporarily removed to the United States. The plan was to have the fossils packed up at PUMC and ready for transfer by the end of November. They were then supposed to be delivered to the United States Legation in Peking and then to the United States Marines Corps barracks stationed next door. The United States Marines were to then take the fossils to the port city of Chingwangtao where they were to be loaded onto the S.S. President Harrison bound for America. The boat was scheduled to depart on December 8. However, the plan did not go according to schedule. In fact, things went terribly wrong.