BEIJING (AP) — Chinese authorities say a homemade bomb was used in an explosion at the front gate of a kindergarten that killed eight people, including the suspect.

Police say the 22-year-old male suspect was identified primarily using security camera footage and DNA collected at the blast scene. They provided only his surname, Xu, but no motive.

Investigators say they found materials for making a homemade bomb at Xu's nearby residence. They say emblazoned on the walls of the residence were the Chinese characters for death and disaster.

The police announcement says Xu had left school because of an autonomic nervous system disorder, whose symptoms can include dizziness and problems with basic bodily functions.

Sixty-five people were injured including eight listed in critical condition.