A Japanese boy was stabbed on his way to school in China on Sept. 18. That’s the date when, nearly a century earlier in 1931, Japan invaded China.

The child, who was 10 years old, was pronounced dead the next morning. The police arrested a 44-year-old man at the scene who they said had confessed to the attack. Japan’s leaders demanded answers. The Chinese government, calling the attack an "isolated incident,” told Japan to calm down and stop "politicizing” the killing.

Some Chinese people believe the boy was a victim of surging anti-Japanese sentiment fueled by China’s government with a virulent nationalism that is taught in schools and reflected online and in state media.