On November 7, 2025, the quiet rhythm of Friday prayers at a Jakarta school mosque was shattered by a series of explosions, leaving 96 people injured and a city grappling with unsettling questions. As details have emerged, the story behind the attack has grown even more troubling: police say the bombing was orchestrated by a 17-year-old student, acting alone and driven by a potent mix of loneliness, online radicalization, and a yearning for recognition in extremist circles.
According to Reuters, investigators quickly honed in on the teenager, who was hospitalized after sustaining injuries in the blast. The attack, which unfolded during one of the mosque’s busiest moments, saw four out of seven homemade bombs detonate, scattering prayer mats, sandals, and glass across the courtyard. The suspect, whose name has not been released due to his minor status, is being treated under Indonesia’s juvenile justice system—a decision that has sparked debate about how to handle such grave acts committed by youths.
The investigation’s most revealing clue came from a 42-page notebook found during a raid of the boy’s North Jakarta home. Titled “Diary Reb”—which police believe stands for “diary of struggle”—the journal was written mostly in English and contained detailed sketches of the mosque and school layout, precise notes on where to plant explosives, and the handwritten date of the attack: November 7. The diary also revealed a deeply troubled mind. As Jakarta police spokesperson Reonald Simanjuntak told Reuters, “He wanted to be recognised by members of the online community … because he feels lonely.” The notebook chronicled not only the technical aspects of the plot but also feelings of isolation, past trauma, and even suicidal intentions. Investigators believe the boy intended to kill himself in the blast, but the device designed for that purpose malfunctioned, leaving him alive and in custody.
The teen’s path to violence, police say, was paved largely in isolation. He lived with his father—a cook for a catering company—in a modest two-storey home in North Jakarta, shared with several boarders. Following his parents’ divorce and his mother’s remarriage, relatives described him as increasingly withdrawn, spending most of his time in his room behind a laptop. “He was always on his laptop in his room,” said Rundiati, a 53-year-old relative who lived with the family, in comments to Reuters. “He became more withdrawn after his parents divorced.” There was, as Simanjuntak put it, “no place for him to express himself, his emotions to his family or to his friends.”
Online, however, the boy found a different kind of community—one that glorified violence and offered the recognition he craved. Investigators say he was active in an international Telegram group that celebrated notorious attacks, including the 2019 Christchurch mosque massacre in New Zealand and the 1999 Columbine High School shootings in the United States. The group, which trafficked in violent content and extremist ideology, provided both technical know-how and a sense of belonging. The suspect reportedly learned bomb-making techniques from YouTube tutorials and sourced materials such as potassium chloride, nails, toy guns, and batteries from online marketplaces—raising serious questions about the ease with which dangerous items can be purchased without triggering alarms.
Telegram, for its part, has stated that such material violates its terms of service and that its moderation systems, including AI tools, remove millions of harmful posts daily. “Moderators using AI tools monitor public areas of the platform and remove millions of pieces of harmful content each day, including material that promotes violence,” Telegram spokesperson Remi Vaughn told Reuters. Google, which owns YouTube, has not commented on the presence of bomb-making tutorials on its platform.
To conceal his plans, the teenager misled his father about his online purchases, claiming they were for cosplay. This strategy allowed him to amass the components needed for seven improvised explosive devices. Four of these detonated in the mosque during Friday prayers, while three failed to explode. The attack, police say, was meticulously planned to maximize casualties—choosing the busiest time at the mosque for the assault.
Authorities are still combing through the teenager’s digital footprint, his diary, and his personal effects to determine if he had any accomplices or if he was influenced by specific networks. So far, police maintain that he acted alone, but the investigation remains open. “Police are continuing their investigation to determine whether other people or networks contributed to the attack, while also deliberating on the appropriate legal measures given the perpetrator’s status as a minor,” Reuters reported.
The attack has reignited concerns in Indonesia about the radicalization of young people through social media and online forums. Just days after the mosque bombing, Indonesian police arrested five suspects accused of recruiting 110 children between the ages of 10 and 18 into terrorism networks. While the mosque bombing was not linked to a specific group, officials say it underscores the broader risks posed by unregulated digital spaces. “The suspected bomber’s case, though not linked to a particular organisation, similarly underscored the risks of radicalising young people through social media,” officials noted at a briefing, according to Reuters.
The suspect’s legal fate is still uncertain. Before any formal charges are brought, Indonesia’s parole and probation office will determine whether the teenager is eligible to stand trial and what form legal proceedings should take. Authorities have not provided a timeline for this decision, and options include handing him over to the state or returning him to his family. The fact that he is being treated as a “child facing the law” under Indonesia’s juvenile crime regulations has prompted discussion among legal experts, policymakers, and the public about how best to balance justice, rehabilitation, and public safety when minors commit such serious offenses.
Meanwhile, the incident has prompted a broader reckoning with Indonesia’s digital security and social welfare systems. The ease with which the teen acquired bomb-making materials online has exposed a worrying gap in marketplace oversight. Police have acknowledged the need to examine how materials like potassium chloride and sharp nails can be purchased with so little scrutiny. At the same time, the suspect’s personal story—a boy from a low-income family, isolated after his parents’ divorce, and drawn into violent online subcultures—has highlighted the urgent need for better mental health support and community engagement for vulnerable youths.
As Jakarta heals from the physical wounds of the attack, the city and the country are left to confront the deeper scars of alienation, radicalization, and the digital age’s dark corners. The case stands as a stark warning of how easily isolation and online extremism can combine to tragic effect, even in places once thought immune to such threats.
