Thai police probe online activity of teen school shooter amid search for motive

Investigators are delving into the digital footprint of a 14-year-old boy accused of a deadly shooting at Debsirin Nonthaburi School, after discovering that he had searched for details about a U.S. school shooting and played violent video games in the days leading up to the attack.

Police have not yet determined a definitive motive, but they are examining whether the teenager's online activity or personal circumstances played a role in the violence that also claimed the lives of his grandparents.

The suspect is believed to have killed his grandparents at their home in Bang Khu Rat subdistrict, Bang Bua Thong district, before heading to school on the morning of August 7, 2026. 

Officers and forensic teams later found their bodies after gaining entry to the property. The front door had been locked from the outside, according to police, suggesting the teen left after the deaths.

Debsirin Nonthaburi School. Photo courtesy: Wikipedia

Provincial Police Region 1 Commissioner Wattana Yichin visited the house as part of the ongoing investigation.

Gaming and Search History Under Scrutiny

Investigators are now analyzing the teenager's computer to piece together his state of mind. Preliminary checks show that he played games with violent themes and had searched for and studied information about a past school shooting in the United States. The searches were recorded from around July 30, police said.

However, authorities have not established a direct causal link between those activities and the shootings. The investigation continues to explore other factors, including any possible problems the boy may have faced at school.

Family Background and Quiet Demeanor

Information provided by the teenager's uncle suggests he had lived with his grandparents since childhood, spent much of his time playing computer games, and was generally withdrawn. Relatives reported no known conflicts, disciplinary issues, or obvious signs of distress before the incident.

The firearm used in the attack was legally registered to the boy's grandfather, according to police.

Thananyaporn, 60 — the younger sister of the deceased grandfather and an aunt of the suspect — said the boy was raised by his grandparents after his parents separated. "They loved him very much," she said. The grandfather would drive him to and from school daily. Unlike other children, he rarely went out, had no close circle of friends, and preferred staying home to play games.

She dismissed the possibility of family tensions, noting that the three were exceptionally close. The grandmother was a teacher and the grandfather a former bank manager who always spoke gently to his grandson. Describing the boy as quiet and polite, Thananyaporn said she never imagined such a tragedy could happen.

Police said the investigation remains focused on establishing a clear timeline and identifying any contributing factors to the attacks.

Bangkok Post adds: Relatives of the 14-year-old suspect in Friday's deadly shooting at Debsirin Nonthaburi School described him as a quiet, well-behaved teenager who spent much of his time playing computer games, while investigators examining his computer found evidence that he had viewed videos of school shootings in the United States in the days leading up to the attack.

The latest findings emerged as police continued trying to establish a motive for one of Thailand's deadliest recent school shootings.

Pol Lt Gen Wattana Yeejeen, commissioner of Provincial Police Region 1, said investigators were analysing the Mathayom 3 student's desktop computer and other digital evidence. Preliminary findings indicated that he played computer games featuring violence, while officers were also examining other online activities that may help explain the attack.

(Source: Straits Times, Bangkok Post)