kenji ota came to indonesia last year and teaches at the university. >> translator: i believe keeping the victims' memory alive will be useful for the next generation. >> reporter: several indonesians studying local history are working and sharing views with oda about the incident. hundreds of japanese, mostly civilians, were reportedly detained at this prison and killed when japanese soldiers refused to hand over their weapons. >> translator: 400 japanese were reportedly cast into tin cells. all of them were said to have died. >> reporter: oda said japanese documents and testimonies suggest the bloody incident prompted the japanese to retaliate with force. but the indonesians have a different story. they took oda to a water purifying facility. >> translator: there was information that the japanese had poisoned the water. that was one reason for the clashes. >> reporter: the group's leader says an indonesian doctor was apparently shot by japanese when he was heading to the facility to check the water. that made people angry. the researchers started to examine their documents together.