According to sources within Jakarta's Police Department, the terrorist made use of homemade pressure cooker bombs. We assume that the terrorist targeted those police officers who were at the bus station to secure an approaching parade organized to welcome the start of the holy month of Ramadan (fasting month).

Whereas in the 2000s Indonesian radical Islamic terrorist were focused on foreign targets (hotels and nightclubs in Jakarta and Bali), most attacks in the past couple of years are targeted at police officers (and sometimes Christian churches). This change of tactics is probably caused by the success of Indonesia's counter-terrorism squad Densus 88 that managed to detect, arrest and - sometimes - kill a significant amount of radical Muslims since its establishment in 2003.

It was reported in Indonesian media that Densus 88 has raided the houses belonging to the two suspected suicide bombers on Thursday (25/05) where they confiscated bayonets, military equipment, as well as official documents such as passports and a marriage license. Family members have been taken in for questioning. One house is located in Bandung (a city in West Java), the other just outside Bandung.

In February 2017 a terrorist was shot dead in Bandung by Indonesian police after he detonated a bomb near a local government office. There were no casualties in this event (except for the terrorist). The terrorist, who had previously been imprisoned for his involvement in the Aceh militant training camp (in 2010 Densus 88 discovered a paramilitary training camp in the jungle of Aceh where - allegedly - attacks were prepared against the Indonesian president and against foreigners and other 'infidels'), was reportedly linked to the terrorist group Jamaah Anshar Daulah (JAD), known as IS sympathizers. The suicide bombers in the East Jakarta bus station may be part of this JAD network as similar devices were used (pressure cooker bombs).

There is a direct link between IS and the small militant Islamic community in Indonesia. According to information from the National Counter-Terrorism Agency (BNPT), released earlier this year, more than 500 Indonesians have joined the war in Syria and Iraq (while it is estimated that more than 100 have traveled back to Indonesia after having fought alongside the militant organization).

The attack at the bus station in East Jakarta is the deadliest terror attack in Indonesia since the bombings and shooting on the streets of Central Jakarta in January 2016 that left eight people dead (including the four terrorists).

Read more: Analysis of Radical Islam in Indonesia