The 17-year-old youth arrested for hijacking a bus and fatally stabbing a passenger last week is giving investigators a detailed account of bullying he suffered at his junior high school, police sources said Monday.

The youth, who was apprehended Thursday after police stormed the vehicle as it was parked at the Kodani service area on the Sanyo Expressway, has so far refused to provide investigators with a motive for his actions.

One of the acts of bullying the teen, from the city of Saga, said he experienced was being forced to jump from the top of a flight of stairs in school.

According to police, the youth, whose name is being withheld because he is a minor, told Saga police a similar story when they were called in by his parents to help in March, when he locked himself into his room and refused to come out.