Police have found a stick that a teen apparently used to beat his 13-year-old girlfriend in a vacant building in Nakatsugawa, Gifu Prefecture, before strangling her, investigators said Sunday.
Other sticks and some cloth were found in a room on the third floor of the former pachinko parlor, leading police to suspect the 15-year-old boy, who was arrested late Friday, used them to kill Nao Shimizu.
They suspect the boy may have known that the cloth and sticks were in the room before he killed her, investigative sources said.
The boy is a first-year high school student. His name is being withheld because he is a minor. Police sent him to prosecutors Sunday on suspicion of murder.