Debsirin Nonthaburi massacre probe reveals the 14-year-old gunman watched violent content, studied firearms and raged over a Thai-language grade. Friends reject bullying claims as police reconstruct the 17-minute school attack that left nine dead.
Police have reconstructed the Debsirin Nonthaburi School massacre almost minute by minute, revealing a 14-year-old gunman with a growing interest in firearms, violent online content and a bitter dispute over a Thai-language grade. Investigators say he killed the grandparents who raised him before attending the morning flag ceremony, entering mathematics class and beginning a 17-minute school attack that left six more dead and 21 injured. Detectives have also uncovered an earlier BB gun incident, a knife carried to school and repeated efforts to find the Thai-language teacher during Friday’s killings. Yet police say no single motive has been established, while friends have strongly rejected claims that sustained bullying drove the attack.
Three days after the Debsirin Nonthaburi School massacre, police are building a fuller picture of the 14-year-old gunman. Investigators are examining his interest in firearms, violent online content and a bitter dispute over a Thai-language grade.
However, police have not identified a single motive for Friday’s attack. Nine people died across two locations, including the teenager himself.
The boy has still not been publicly named because of his age. Nevertheless, police have reconstructed much of Friday’s attack almost minute by minute. His grandparents were the first victims. Police say he shot them at home with his grandfather’s 9mm pistol, a CZ 75 Compact semi-automatic. Afterwards, he travelled to Debsirin Nonthaburi School in Bang Kruai district, Nonthaburi.
Teenager follows normal school routine before opening fire as police uncover growing interest in guns
At school, the teenager initially followed his normal routine. He joined the morning flag ceremony with other students. He then went to class without drawing attention. Yet, within minutes, he began shooting teachers and students.
Six people were killed at the school before the boy took his own life. Another 21 people were injured, including 19 students and two teachers.
Meanwhile, investigators have uncovered an earlier fascination with guns. Pol Maj Gen Atthapol Anusit, deputy commissioner of Provincial Police Region 1, briefed reporters on Sunday. He said the boy’s interest in firearms stretched back between one and two years. “According to witness interviews, the perpetrator had begun showing interest in studying the use of firearms for some time, about one to two years,” he said.
Police initially interviewed 17 witnesses, including teachers, classmates and close friends. Subsequently, the inquiry widened to more than 20 teachers and students. Officers also examined the teenager’s old mobile telephone and personal computer. Significantly, those devices became a major strand of the inquiry into his behaviour before the killings.
Police find violent online content but no evidence teenager ever received formal firearms training
“After examining the PC, it was found that the child had watched social media content involving violence,” Pol Maj Gen Atthapol said. In addition, investigators found that the teenager had used social media to learn about firearms. However, police found no evidence that he had attended a shooting range. Nor did they establish that he had received formal firearms training.
Separately, detectives uncovered an earlier school incident involving a BB gun. The teenager had bought the air gun online last year. He then carried it into Debsirin Nonthaburi School inside his bag. According to a close friend, he showed the weapon to classmates and used it around the school grounds.
Eventually, another student reported the BB gun to teachers. A teacher confiscated the weapon and deducted points from the teenager’s conduct record. The punishment was imposed under school rules. Notably, investigators have also learned that the teenager previously carried a knife to school. Police later recovered a knife during Friday’s investigation.
Officers also seized the grandfather’s 9mm pistol, spent cartridge cases and other physical evidence. As part of this, detectives are trying to establish where the live ammunition came from. They are also examining how the teenager gained access to it. The handgun belonged to his grandfather, placing firearm storage under close scrutiny.
Family inquiry reveals quiet home life as police examine school dispute over failing Thai-language grade
On another front, police are examining the teenager’s family background. His parents separated when he was very young. Afterwards, his grandparents raised him from approximately two years of age. He had lived with them for about 12 years before Friday’s killings.
Yet relatives described a quiet teenager who caused little trouble at home. His grandmother’s sister said he generally kept to himself. She said he went to school in the morning and returned home on time. Moreover, he usually stayed home during weekends rather than visiting friends.
The relative also said he played computer games. However, she did not know which games he used. Crucially, she rejected suggestions that the grandparents had placed excessive pressure on him. Instead, she described a well-behaved child who was not easily influenced by friends.
In parallel, investigators are comparing that family picture with evidence from school. One issue has surfaced repeatedly in witness interviews. It concerns a Thai-language teacher and a failing grade of zero. The teenager was generally regarded as academically capable, but classmates said he struggled with Thai language.
Students say teenager repeatedly complained about zero grade and searched for Thai-language teacher
In particular, he complained repeatedly about the volume of homework and assignments. More importantly, the zero grade became a persistent source of frustration. According to one close friend, the boy tried several times to make up the result. Eventually, he passed, but the dispute remained a recurring subject.
One classmate recalled a specific grievance. The teenager said: “I submitted all my assignments, but my grades weren’t changed.” Another student gave investigators a similar account. According to that witness, the teenager had never previously failed a subject. His Thai-language results were not outstanding, but the zero was reportedly his first failure.
Against that background, police are preparing to question the teacher concerned. She has not been accused of wrongdoing. More strikingly, several students say the teenager searched for that teacher during Friday’s attack. Reports indicate she was not teaching at school that day. Even so, witnesses say the gunman tried to find her.
One male student later confirmed that detail to investigators. He said the teenager was indeed searching for the Thai-language teacher. According to student information, the gunman later moved to Building 4 while looking for her. He failed to find the woman.
Police examine several possible factors after witnesses reject reports of sustained bullying at school
Afterwards, witnesses said he became frustrated and fired three shots into the air. Soon after, he took his own life. However, police have not declared the grade dispute the motive. Instead, investigators are examining it alongside several other factors.
Pol Maj Gen Atthapol said those factors included family issues, studies, friendships and violent online content. “We found that several factors may have combined, including family issues, studies, friendships and the consumption of violent content on social media,” he said. Therefore, police are resisting attempts to reduce the massacre to one trigger.
Possible bullying has also been examined. Yet one close friend strongly rejected reports that classmates had tormented the teenager. The student had known him from Matthayom 1 through Matthayom 3, covering Grades 7 to 9. He described the boy as quiet and withdrawn.
Usually, the teenager sat in the far-left corner at the back of the classroom. Nevertheless, his friend insisted he was never bullied, harassed or physically attacked during those three years. Furthermore, the witness rejected specific stories circulated after the massacre.
Those claims included reports that other students had kicked the teenager into a bathroom. According to the friend, the stories were false. He also said the boy held no known grudge against classmates. Nor was he regularly involved in arguments with other students.
Prime Minister urges caution over bullying claims as police reconstruct stages of deadly school attack
The repeated grievance, he said, concerned the Thai-language teacher. Prime Minister Anutin Charnvirakul has also urged the public not to assume bullying caused the killings. He said investigators must first establish the facts. At the same time, Mr Anutin addressed the boy’s legal position.
The Prime Minister told foreign reporters the teenager was not criminally responsible because of his age. He also referred to stress at school and other factors surrounding the attack. However, police have not settled on one cause. Instead, detectives are examining family life, academic pressure, friendships and online activity.
The attack itself has now been reconstructed in four stages. Friday began normally at the school. The teenager attended the morning flag ceremony alongside his classmates. Afterwards, he entered class and took his usual place. No obvious confrontation or unusual atmosphere was reported.
The shooting began during the second lesson, which was mathematics. At the time, the teacher was explaining homework and preparing students for revision. A close friend was inside the classroom and later described the moments before the shooting.
According to that witness, the teenager had been sitting down for about ten minutes. He then put in earplugs. Next, he stood from his desk at the back and walked towards the front. The boy was carrying ammunition.
Friend recalls no warning signs before teenager opened fire during second-period mathematics lesson
There had been no warning signs, according to the friend. “Before the shooting, there were no warning signs or any tense atmosphere,” he said. At approximately 9.53 am, the teenager shot a teacher in Classroom 3/8 on the sixth floor.
He then left the room and continued through the school. Almost immediately, he moved to Room 565. Two teachers were killed there, while a student was also shot. By approximately 9.54 am, the teenager was moving towards the fifth floor.
He then inserted a fresh magazine into the pistol. At that point, police said the handgun apparently jammed. Even so, the malfunction did not stop the attack. Instead, the teenager continued towards the fourth floor.
There, he shot the school’s deputy director and the director’s secretary. By then, emergency calls had already brought police towards the campus. A uniformed patrol from Plai Bang Police Station reached the school at approximately 10.02 am.
That placed police on the scene roughly nine minutes after the first fatal classroom shooting. One minute later, officers requested additional support. However, the gunman was still moving through the school.
Police arrive nine minutes after first classroom killing as gunman continues moving through school
Police said he passed through the third, second and first floors. During that period, he fired towards groups of teachers and students. Notably, investigators also established that he encountered a school janitor.
The teenager did not shoot him. According to police, the boy spared the janitor because he was not a teacher. From there, the gunman headed towards Building 4 while reloading his pistol.
By 10.08 am, officers were attempting to communicate with him. They ordered him to stop shooting. Two minutes later, at approximately 10.10 am, the teenager took his own life. Tactical police later entered Building 4 and cleared the area.
Consequently, the active school attack lasted about 17 minutes from the first fatal shooting. Police patrol officers arrived while the attack was still underway. However, the killing had started earlier at the family home.
Before reaching school, the teenager had already shot his grandparents dead. The weapon belonged to his grandfather. Police are therefore examining its storage and the boy’s access to it.
In response, Mr Anutin has warned gun owners about their legal responsibilities. He said owners could face prosecution if weapons were stolen and later used in crimes. The Prime Minister also called for tighter enforcement against people carrying firearms in public.
PM warns gun owners over legal responsibility as police examine access to grandfather’s pistol
Those carrying guns without legal authority could face serious criminal charges, he said. However, Mr Anutin rejected suggestions that teachers should carry guns for self-defence. Teachers are not law-enforcement officers, he said.
Meanwhile, the Ministry of Education has announced new school security measures. Officials expect to develop the protocols during the next three months. Among them will be mental-health screening and procedures for referring at-risk individuals to specialists.
Emergency response drills are also planned. Additionally, the ministry intends to strengthen measures against bullying. Detection systems will also be improved to stop prohibited items from entering schools.
The BB gun incident has now taken on greater significance. The teenager had already carried one weapon onto the campus. Another student eventually reported him, leading to its confiscation.
The knife incident has also become part of the inquiry. Police say he previously carried a knife in his school bag. Taken together, those episodes are being examined alongside his online activity.
However, investigators have not established that he previously used a real firearm. Likewise, they have found no evidence that he received organised firearms training. Instead, evidence indicates he learned about guns through online media.
Education Ministry plans tighter school security as earlier BB gun and knife incidents draw scrutiny
Police say that interest developed over one or two years. Furthermore, his computer contained evidence of violent online viewing. Detectives are now comparing that digital trail with the physical evidence collected after Friday.
At the same time, ammunition remains another unresolved question. Police want to know where it came from. They also want to establish when the teenager gained access to it.
His parents have returned for further questioning. On Sunday, the boy’s father briefly addressed reporters after giving another statement. He raised his hands in a wai.
“Sorry to the victims,” he said. Reports said he also told investigators that he could not understand his son’s actions. The family evidence now sits alongside detailed accounts from classmates and teachers.
Those accounts present several sharp contrasts. Friends described the teenager as quiet, withdrawn and academically capable. They denied that he had been subjected to sustained bullying. Yet they also remembered his recurring anger over the Thai-language grade.
They knew about the BB gun as well. One friend remembered him bringing it to school and displaying it to classmates. Students also watched him fire the air gun around the grounds before teachers confiscated it.
Police trace gun interest over two years as ammunition source and family questioning remain unresolved
That incident led to disciplinary action. One year later, the teenager entered the same school carrying his grandfather’s 9mm pistol. Before arriving, he had already killed the grandparents who had raised him for most of his life.
Even so, he lined up for the flag ceremony as usual. He then went into mathematics class with his classmates. There was no visible confrontation beforehand, according to the friend sitting nearby.
Then the teenager put in earplugs. He stood up, carried ammunition towards the front and shot the teacher. Within minutes, he was moving through classrooms and corridors.
Teachers, students and senior school staff were hit. Police reached the campus at 10.02 am. Six minutes later, officers were trying to persuade the teenager to stop. By approximately 10.10 am, he was dead.
Nine people were dead across the home and school. Another 21 were injured. Since then, investigators have been separating verified evidence from claims circulated after the massacre.
Bullying is one example. Mr Anutin has cautioned against declaring it the cause before police complete their work. The teenager’s close friend has gone further and directly rejected reports of sustained bullying.
Friends recall BB gun incident as investigators contrast quiet behaviour with anger over school grade
By contrast, the Thai-language dispute is supported by several student accounts. Friends say the teenager repeatedly complained about the teacher and the zero grade. One grievance was especially specific.
“I submitted all my assignments, but my grades weren’t changed,” the teenager reportedly told a friend. Witnesses also say he searched for that teacher during the attack. She was apparently not teaching at the school that day.
The teenager reportedly went to Building 4 looking for her. He could not find her. Shortly afterwards, witnesses said he fired three shots into the air. Then he took his own life.
Even so, police have not labelled the teacher dispute as the motive. Instead, detectives say several strands remain active. They include family circumstances, academic pressure, friendships and school life.
The boy’s violent online viewing is another significant area. So is his growing interest in firearms. Police now hold a substantial collection of evidence.
They have the grandfather’s 9mm handgun, spent cartridge cases and ammunition evidence. They also have a knife, the teenager’s computer and his old mobile telephone. Beyond that, officers have testimony from teachers, classmates, close friends and family members.
Police separate evidence from rumours. Bullying claims rejected but Thai-language dispute examined
Police have also reconstructed the attack to individual minutes. What remains unresolved is what drove the teenager to act. Investigators know his interest in firearms developed over one or two years.
They know he purchased a BB gun online. They know he brought it to school and showed it to friends. They also know he fired it around the campus before a teacher confiscated it.
Furthermore, they know he previously carried a knife in his school bag. Investigators also know he watched violent material online and used social media to study firearms.
Yet they have found no evidence of formal shooting instruction. At school, police have documented his repeated frustration over Thai language. Friends say he complained frequently about the teacher and failing grades.
Several witnesses also say he searched for that teacher during Friday’s killings. At the same time, friends have rejected claims that long-term bullying drove him.
Detectives hold gun, ammunition and digital evidence as several possible motives remain under examination
Relatives have also described no serious history of trouble at home. His grandmother’s sister described a quiet teenager who usually returned home on time. She said he generally stayed home at weekends.
However, Friday began with the deaths of the two grandparents who raised him. It then shifted to the school where he had studied for three years. Within about 17 minutes, six people were dead there.
All seven injured in Friday’s school shooting are now out of danger. Public continues to lay flowers at scene
Anutin blames stress at the scene of Friday’s school massacre. Told reporters no crime was committed
Police arrived while the shooting was still continuing. Minutes later, officers had reached the area where the teenager ended the attack. They attempted to communicate with him.
At approximately 10.10 am, the teenager took his own life. Three days later, he remains publicly unnamed. However, investigators now possess a detailed record of his final movements.
They also have his digital history, school record and earlier weapons incidents. Most notably, they have repeated witness accounts concerning the Thai-language dispute. Police are now testing each strand against the evidence before settling on what drove Friday’s nine deaths.
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