A 14-year-old Mathayom 3 student opened fire at Debsirin Nonthaburi School on Friday, killing eight people (including five teachers) and injuring at least 22. He first shot his grandparents at home before proceeding to school. Relatives describe him as quiet and well-behaved, spending most time on computer games. Investigators found evidence he had viewed US school shooting videos since late July—about a week before the attack. Police are examining whether violent video games, online content, or prior firearms training influenced his actions, but have not yet established a direct causal link.