Japanese forces first landed in Miri on 16 December 1941, and conquered Kuching on 24 December. On 25 December, Sibu was bombed by 9 Japanese warplanes flown from Kuching. The Resident of the Third Division, Andrew MacPherson, believed that the Japanese would start to invade Sibu following the air attack. He and his officer later fled Sibu to the upstream of Rajang River. They planned to pass through Batang Ai and trek through the forests to reach Dutch Borneo. However, they were caught and killed by the Japanese at Ulu Moyan, Sarawak.