Two suicide bombers who attacked an Indonesian cathedral on Palm Sunday were newlyweds who joined a pro-Islamic State extremist group, police said Monday, as they arrested others suspected in the plot.
About 20 people were wounded in the powerful explosion outside the church in Makassar city on Sulawesi island while worshippers celebrated the start of Holy Week.
Both suspects were killed instantly after they rode a motorbike into the church compound and, when challenged by security, detonated a bomb packed with nails, police said.
They were the only fatalities.
About 15 victims remained in hospital Monday, with two in intensive care for burn injuries. Four have been discharged.
On Monday, Indonesian authorities said the pair, identified through DNA and fingerprint testing, had been married for about six months.
The male suspect, who was in his mid-twenties, left his family a suicide note that said he was ready to die as a martyr.
The couple belonged to an Islamic study group along with several of more than a dozen other suspects arrested since Sunday over their alleged roles in the attack, police said.
"They each had their own role, including buying the ingredients, teaching bomb making, creating the explosives and using them," National Police Chief Listyo Sigit Prabowo told reporters.
Raids at several locations including at the couple's home in Makassar and others in Indonesia's capital Jakarta turned up a cache of powerful explosives and bomb-making ingredients, authorities said.
Sunday's attack came after the arrest of dozens of suspected militants in recent months by Indonesia's counter-terror squad.
A Makassar resident said the male bomber was a street food seller who lived in a rented house near his parents' home.
"He was nice as a kid... but when he got older he didn't really socialise around here," Nuraini, who like many Indonesians goes by one name, told AFP.
Police said the couple were members of Jamaah Ansharut Daulah (JAD), an extremist group blamed for series of attacks, including 2018 suicide bombings at churches in Indonesia's second-biggest city Surabaya, which killed a dozen congregants.
Sunday's explosion at the main Catholic cathedral in Makassar happened just after congregants finished celebrating Palm Sunday, the first day of Holy Week, which commemorates Jesus's entry into Jerusalem.
It comes a week before Easter.
JAD was also implicated in a 2019 cathedral suicide bombing in the Philippines committed by a married Indonesian couple. That attack killed worshippers and security forces.
Indonesia, the world's biggest Muslim majority nation, has long struggled with attacks by Islamist extremists, including the 2002 Bali bombings which killed more than 200, mostly foreign tourists.