People leave flowers outside Debsirin Nonthaburi secondary school the day after a 14-year old student shot dead 5 school staff, after also killing his grandparents at home. [AFP]
A 14-year-old boy who shot dead the grandparents who raised him before killing six others at his school in Thailand had watched violent videos online and once brought a BB gun to school, police said Sunday.
The teenage assailant shot his grandparents, using his grandfather's handgun, at their home north of Bangkok on Friday before going on a killing spree at his secondary school and ultimately turning the gun on himself, according to authorities.
A 12-year-old girl wounded in the school shooting died on Saturday, and five teachers and school staff were killed on Friday, police said.
Investigators interviewed 17 witnesses and were examining the boy's computer and phone to determine the "real cause of the shooting", Atthapol Anusit, a deputy police commander for the region surrounding the capital, told reporters on Sunday.
"We looked into his PC and found history that he watched violent videos on social media," Atthapol said.
"From questioning the kids, we know that he brought a BB gun to school last year but a teacher seized it."