The shocking explosion that rocked SMA 72 High School in North Jakarta on October 7, 2025, has sent ripples through Indonesian society and beyond, exposing the dark corners of online radicalization and raising urgent questions about youth safety in the digital era. The attack, carried out by a 17-year-old student, injured 96 people—including many students—after a series of homemade explosives detonated in the school mosque. As details have emerged, the case has revealed a disturbing nexus of extremist ideology, social isolation, and the unregulated spread of violent content online.
According to reports from Yonhap News and corroborated by The Asia Business Daily, the teenage suspect meticulously planned the attack over several months. Investigators discovered that he had joined extremist channels on Telegram, a messaging app notorious for its lax moderation. These channels, police say, glorified white supremacist mass shootings, such as the 2019 Christchurch mosque massacre in New Zealand and the 2015 Charleston church shooting in the United States. Both attacks were perpetrated by individuals motivated by white supremacist beliefs, and the suspect appeared to idolize these figures, even attempting to emulate their crimes.
Evidence found at the scene painted a chilling picture. The suspect left behind a toy submachine gun inscribed with phrases like "Brenton Tarrant: Welcome to Hell," referencing the Christchurch attacker, as well as "Dylan Roof," "KKK" (Ku Klux Klan), and the "14 words," a slogan commonly used by white supremacists. Police interpreted these markings as clear signs of the boy's deep immersion in violent, racist ideologies encountered in online spaces. "He was drawn into violent ideologies encountered on Telegram, idolized the perpetrators of these mass shootings, and attempted to emulate their crimes," local authorities told The Asia Business Daily.
The investigation further revealed that the suspect learned bomb-making techniques by watching YouTube videos, assembling seven small improvised explosive devices at home. Four of these detonated during the incident, while three failed to explode. He procured bomb-making materials such as potassium chloride and nails, along with toy guns, from online marketplaces—deceiving his father by claiming the items were for cosplay. The ease with which these dangerous materials were acquired online has prompted police to probe regulatory gaps and consider new safeguards for online commerce.
Perhaps most unsettling was the discovery of a 42-page diary at the suspect's home. The diary contained detailed sketches of the school and mosque layouts, precise bomb placement locations, and a timeline for the attack. It also offered a window into the suspect's psyche, revealing feelings of isolation, past trauma, and a grim desire to end his own life by harming others. Relatives described him as increasingly withdrawn following his parents' divorce, spending most of his time alone in his room and rarely interacting with others. "He had no one to express himself or his feelings to, whether family or friends," a police official told Reuters, underscoring the boy's profound sense of alienation.
As the investigation unfolded, the suspect himself was hospitalized after being injured in the blast—his suicide device failed to function as intended. Metro Jaya Police spokesperson Senior Commissioner Budi Hermanto told ANTARA News that "he is still disoriented and occasionally incoherent, showing he has not fully recovered." The police have officially classified him as a "child in conflict with the law," or ABH, a designation for minors involved in criminal cases in Indonesia. Authorities are waiting for doctors to clear the suspect medically before proceeding with formal questioning, and are coordinating with the Probation Office, Social Services, and the Indonesian Child Protection Commission to ensure his rights and welfare are protected during the process.
In the meantime, the police have been gathering testimony from witnesses, family members, forensic labs, and medical personnel. "Yesterday we focused on gathering testimonies from witnesses, the suspect’s family, forensic labs, and psychological assessments," Budi Hermanto said on November 20. Three victims of the explosion remain hospitalized at Yarsi Hospital, Cipto Mangunkusumo Hospital, and the Indonesian National Police Hospital, and authorities continue to provide support to those affected by the tragedy.
Indonesia’s Densus 88 Counterterrorism Unit has shed further light on the ideological influences that shaped the suspect’s actions. According to Densus 88 spokesperson Adjunct Senior Commissioner Mayndra Eka Wardhana, the suspect drew inspiration from at least six violent figures, including Eric Harris and Dylan Klebold—the perpetrators of the 1999 Columbine High School attack in Colorado, who espoused Neo-Nazi ideology. Neo-Nazism, a far-right movement that revives Nazi German ideology, emphasizes Aryan racial supremacy and hatred toward minority groups. The suspect’s exposure to these figures, combined with his online activity, appears to have played a significant role in his radicalization.
The case has prompted a wider debate in Indonesia about the influence of digital platforms and violent content on young people. President Prabowo Subianto, after receiving a police report on the high school bombing, instructed his cabinet to review regulations related to computer games—echoing policies in South Korea that aim to curb youth exposure to violent gaming. As reported by Bloomberg and Russian state-run TASS News Agency, President Prabowo suggested that the incident may be linked to the influence of violent computer games on youth, sparking controversy and discussion about the balance between digital freedoms and public safety.
This tragedy has also spotlighted broader issues of school safety, mental health, and the challenges faced by children from broken or low-income families. In the wake of the explosion, Indonesia’s Ministry of Education has pledged to strengthen safe school policies, and officials have called for joint efforts to prevent bullying and radicalization among students. The ongoing investigation, meanwhile, continues to emphasize caution due to the suspect’s medical and psychological condition, with authorities vowing to leave no stone unturned in understanding the full scope of what led to the attack.
As Indonesia grapples with the aftermath of the SMA 72 explosion, the case stands as a stark reminder of how online extremism, unregulated digital content, and social isolation can converge with devastating consequences. The lessons learned here will likely shape national debates on digital regulation, youth protection, and mental health for years to come.