Indonesian police on Friday arrested three men on suspicion of links to the brazen attacks in the heart of the country's capital, and said they recovered an ISIS flag from the home of one of the attackers. The discovery of the flag bolsters authorities' claim that the attack Thursday was carried out by ISIS, which has attracted hundreds of foreign fighters from Malaysia and Indonesia to its "caliphate" in Iraq and Syria. Five men attacked a Starbucks cafe and a traffic police booth in Jakarta with hand-made bombs, guns, and suicide belts Thursday, killing two people—a Canadian and an Indonesian—and injuring 20. The attackers were killed subsequently, either by their suicide vests or by police.
The ISIS link, if proved, poses a grave challenge to Indonesian security forces because until now the group was known only to have sympathizers with no active cells capable of planning and carrying out such an attack. In recent years Indonesian anti-terror forces had successfully stamped out another extremist group known as Jemaah Islamiyah. It was responsible for several attacks in Indonesia, including the 2002 bombings of bars in Bali, which left 202 people dead. Jakarta residents were shaken by Thursday's events but refused to be cowed. Onlookers and journalists lingered near the Starbucks cafe, with some people leaving flowers and messages of support. A large screen atop the building displayed messages that said "#prayforjakarta" and "Indonesia Unite."