The attacker was Patchat Yimruang, a 14-year-old Mathayom 2 (8th grade) student at the school . Classmates described him as "troubled" and "bullied," and police said he had told a close friend he was under stress and would "do something that would shock everyone" . He lived with his grandparents after his parents separated .
At least 22 people were injured, 9 of them seriously . Some reports say "over 30" were injured . Deputy Interior Minister Polapee Suwunchwee stated that 15 of the injured students were hurt while fleeing, not by gunfire . Two children were placed in intensive care .
The shooter used a 9mm handgun, legally registered to his grandfather, a former teacher . Police confirmed the weapon was taken from the grandparents' home .
Debsirin Nonthaburi School is a co-educational state secondary school in Bang Kruai district, approximately 20 km northwest of Bangkok. It serves students aged approximately 12–18 (Mathayom 1–6). It is a secondary institution, not an elementary school .
The shooter told a close friend he was under stress connected to school . Prime Minister Anutin Charnvirakul publicly attributed the shooting to "academic stress" after police interrogated the suspect's close friend . A classmate described Patchat as "troubled and bullied" . Police believe the attack was planned . Some media reports also described the teenager as a "fanatical gamer," though this was not officially confirmed as a motive .
Thailand has one of the highest rates of civilian gun ownership in Southeast Asia, with an estimated 10.3 guns per 100 people (over 7 million legal and illegal firearms) . This shooting was the deadliest mass killing in Thailand since the 2022 Nong Bua Lamphu nursery attack, in which a former police officer killed 36 people . It was the second school shooting in Thailand in 2026, following a February incident in Hat Yai in which a teacher was killed and a student injured .
Parents rushed to pick up their children, and tearful students and staff comforted each other outside the school . Deputy Interior Minister Polapee Suwunchwee said the incident was "such a tragic and shocking event" . Thai authorities also appealed to the public and media to refrain from sharing images or videos that may affect the feelings of the bereaved . The government pledged stricter gun control measures, and Prime Minister Anutin said such an incident must not be allowed to happen again .