An explosion at a kindergarten in eastern China that killed eight people and injured dozens more Thursday afternoon was a deliberate attack by a mentally unstable man, Chinese state-run media reported.

The Xinhua news agency, citing police, reported that investigators found bomb-making materials in the suspected bomber's home, along with the words "death" and "end" scrawled on the walls.

Police said the 22-year-old man, who had a history of mental illness, lived and worked near the kindergarten. He reportedly was suspended from his school because of a nervous system disorder.

He was killed in the blast outside the Chuangxin Kindergarten in Xuzhou's Fengxian county. The attack occurred at 4:50 p.m. local time as parents were waiting to pick up their children at the end of the school day.