Jakarta. Police revealed new findings in last week’s Jakarta school bombing, saying the teenage suspect behind the explosion that injured nearly 100 people had been inspired by global mass shooters and was active in online groups that glorified violence.

The November 7 explosions struck SMA Negeri (state high school) 72 Jakarta’s mosque during Friday prayers, wounding 96 students and teachers. As of Tuesday, 28 victims remain hospitalized in one of Indonesia’s most serious school-related incidents in recent memory.

The suspect -- a student at the same school -- remains under treatment at the Bhayangkara Police Hospital with serious head injuries. His identity has not been released because he is a minor.

Investigators from the police counterterrorism unit Detachment 88 found that the student had been following internet groups promoting extremist ideology and had drawn inspiration from at least six mass attacks abroad, said unit spokesperson Mayndra Eka Wardhana.

“We discovered disturbing evidence. Several figures appear to have influenced the suspect’s actions,” Mayndra told a press briefing in Jakarta.

According to the digital forensics analysis, the perpetrators the student idolized included:

• Eric Harris and Dylan Klebold, Columbine High School shooters (U.S., 1999)
• Dylann Roof, Charleston church gunman (U.S., 2015)
• Alexandre Bissonnette, Quebec mosque shooter (Canada, 2017)
• Vladislav Roslyakov, Kerch Polytechnic College attacker (Crimea, 2018)
• Brenton Tarrant, Christchurch mosque shooter (New Zealand, 2019)
• Natalie Lynn Rupnow, Abundant Life Christian School shooter (U.S., 2024)

Police said the names of some of these attackers were written on the suspect’s toy rifle, recovered at the blast site, alongside the phrase: “Brenton Tarrant - Welcome to Hell.”

“Findings like these demand collective awareness -- not only from law enforcement but also from educators, families, and the online environments surrounding our children,” Mayndra said.

Homemade Nail Bombs and Remote Detonation
Forensic analysis showed that the bombs used in the attack were crude but highly dangerous, built with potassium chloride as the main explosive and nails packed inside as shrapnel.

“The devices contained potassium chloride and nails scattered throughout the mosque after the blast,” said Chief Commissioner Henik Maryanto, commander of the Jakarta Police Mobile Brigade.

Police said the suspect brought seven bombs to the school -- two exploded inside the mosque, four were later found near the school’s waste area, and one in the library. Three of the devices failed to detonate and were later defused and sent for forensic testing.

Some devices used A4 batteries, a remote-controlled trigger, and one-liter plastic containers as casings. The bomb fragments and a toy rifle were seized as evidence.

“The explosions were remotely triggered using a 6-volt transmitter and receiver system,” Henik said.

Surveillance footage showed the suspect arriving at the school on Nov. 7 carrying two large bags, believed to contain bomb components, said Jakarta Police spokesperson Bhudi Hermanto.

“The suspect came to school with a tote bag and a backpack. Those were among the key pieces of evidence,” Bhudi said, adding that three bombs failed to ignite due to incomplete fuse connections.