
In the mid-morning of 28 March, worshippers filled the Sacred Heart of Jesus Cathedral in Makassar—the largest city on the Indonesian island of Sulawesi—for a Palm Sunday service marking the start of the Holy Week leading up to Easter. At 10.30am, just as mass was ending, the force of a powerful explosion ripped through a side entrance to the church, injuring 20 people. No churchgoers were killed, but found among the debris were the body parts of two people who had not attended the service that morning—they were Islamist suicide bombers, who had pulled up on a motorbike and detonated their device.
Authorities said the attackers, later revealed to be a husband and wife, were affiliated to local militant group Jamaah Ansharut Daulah (JAD). Indonesian president Joko Widodo—leader of the world’s largest Muslim-majority nation—condemned the assault as an ‘‘act of terror’’ that went against Islamic values.
Just three days after the bombing, on 31 March, a woman radicalized by ISIS ideology opened fire in a ‘‘lone wolf’’ attack before being shot dead by police officers at the headquarters of the National Police in Jakarta. This led to fears of repeat attacks over Easter, which fortunately did not materialize; yet the attacks last month were among the most serious in Indonesia since a spate of suicide bombings in the East Javan city of Surabaya in May 2018, which killed scores of civilians. Like the Makassar attack, those blasts were perpetrated by families of bombers linked to JAD. Is the militant threat now rising again?
Disparate terror networks
Investigations in the aftermath of the Makassar blast have revealed much about the nature of militant activity in Indonesia. The couple who perpetrated the attack were born in the 1990s, and were recently married. They have joined a growing list of Indonesian jihadists to have blown themselves up in suicide attacks together as a couple, while some have even involved their children in attacks. The phenomenon reflects ISIS ideology that glorifies involving children in jihad and seeking martyrdom as a family unit.
In the Surabaya blasts three years ago, which also targeted churches, six of the attackers came from the same family, including several young children. A similar attack in January 2019 on a Catholic cathedral in Jolo, in the southern Philippines, was also carried out by a young Indonesian couple who had joined Abu Sayyaf. That attack left 22 people dead and more than 100 injured, in addition to dozens killed earlier in Surabaya. Indonesian authorities have said the bombers in those incidents also had close ties to JAD.
JAD is more of a collection of cells, inspired by jihadist ideology and online propaganda, than a coherent or hierarchical organization, making it difficult for intelligence agencies to track and disrupt. The militant network can be thought of as an unstructured alliance between small, radical groups, in which members are often related to one another, or have close links through friendship and online activity. ISIS ideology unifies JAD with a separate group, Mujahideen Indonesia Timur (MIT), operating out of Poso, Sulawesi.

The Makassar suspects used a pressure cooker bomb, which the head of Indonesia’s National Counter-Terrorism Agency (BNPT), Boy Rafli Amar, said was constructed after ‘‘online training on social media’’, which allowed the two suspects to ‘‘develop the procedure for making explosives’’. Others likely aided the couple ahead of the bombing, and police have since detained four members of a Koran study group attended by the attackers. After those arrests, National Police chief Gen. Listyo Sigit Prabowo said each had played a role to ‘‘spread doctrine, plan for jihad’’ and ‘‘buy materials’’ used to make the bomb.
In further raids related to the attack, 13 people were detained across Makassar, Jakarta and West Nusa Tenggara—evidencing the geographical spread of those involved—while security forces seized 5.5kg of explosive materials including triacetone triperoxide (TATP), a bomb component often used by jihadists.
While a small network was discovered in relation to the Makassar attackers, the woman who opened fire at the National Police headquarters in Jakarta three days later, identified as 25-year-old ex-student Zaikah Aini, is thought to have acted alone. In this case, police cited online radicalization as a prominent factor, after the suspect posted an ISIS flag on her social media account before launching the attack. ISIS sympathizers unable to join the 700 or so Indonesians who have travelled to fight in Syria and Iraq since 2014 have been encouraged by ISIS, via its network of online channels, to launch attacks in Indonesia.
Jemaah Islamiyah threat
Besides the threat from diffuse networks, there remains an organized element to Indonesian militancy in the form of Jemaah Islamiyah (JI), a group which committed a succession of mass-casualty assaults in the early part of this century; most notably the Bali attacks in 2002 and hotel bombings in Jakarta in the following years, claiming hundreds of lives. JI was banned in court but has still been allowed to conduct social, educational and religious activities on the understanding that it renounces its violent tactics.
Yet there are recent signs that JI is regrouping, and is no longer committed to non-violence. Last year, police accused the group of using cash from charity donation boxes, placed in restaurants and stores in seven provinces, to fund terrorist activities and send jihadists abroad for training. Police seized 31 such boxes in raids in March. Authorities have also arrested JI figures who may still have harbored ambitions to restart attacks, detaining senior JI military commander Aris Sumarsono—also known as Zulkarnaen—in December, who had spent 18 years on the run. He had been sought by police since the Bali blasts.
More recently, a sizeable JI cell was discovered in East Java earlier this year, commanded by Usman bin Sef—also known as Fahim. Fahim was among 22 suspects arrested in police raids in late-February and early-March. Police allege he was training new JI members in Malang district and had built a bunker for storing weapons and constructing bombs. Authorities have seized pistols, knives, swords and machetes from Fahim’s followers, and uncovered materials detailing a plot to attack on-duty police officers.

After further raids, a total of 49 members of the Fahim-led cell are now in custody. Yet might more be unaccounted for, and do other such groups exist? Aswi Siregar, the head of Detachment 88, Indonesia’s elite police counter-terror force, told a press conference his unit would ‘‘continue to hunt them down’’.
A rising terror threat?
Militants were deterred from carrying out fresh attacks over easter, with security stepped-up at police stations and places of worship nationwide. Yet as law enforcement operations after the Makassar blast continue, a short-term threat persists as militants wary of being detained may choose to act with haste to avoid their plots being disrupted. Longer term, networked cells affiliated to JAD will continue to pose a major challenge as will the remnants of MIT and JI, and individuals inspired by ISIS propaganda online.
Indonesian authorities are fighting a constant battle against Islamist terrorism. In an in-depth interview in January with Channel News Asia, BNPT director of enforcement Brig.-Gen. Eddy Hartono warned that terror cells are ‘‘actively recruiting, spreading their ideology, raising funds and conducting training’’ and described the threat to Indonesia as ‘‘omnipresent’’. In particular, he cited a risk of radicalization due to the COVID-19 pandemic, with terrorist recruiters able to exploit the economically vulnerable in society.
Indonesia will continue with its multi-pronged strategy. Visible police operations are just the public face of these efforts—monitoring of social media, deradicalization programmes in prisons, and a civil society drive to contest the extreme narratives peddled by radical preachers, are all equally as important as law enforcement raids. These measures limit the damage; but with online propaganda raising the appeal of homegrown groups like JI and JAD, preventing all events like the Makassar bombing is an arduous task.
A version of this article is also published on Geopolitical Monitor.