Jakarta. Preliminary investigations revealed that the suspected suicide bomber of Wednesday's (24/05) attack in East Jakarta had links to an Islamic State sympathizer who detonated a low-explosive bomb in Bandung, West Java in February, police said on Thursday.

According to investigations into Wednesday's attack — where two suspected suicide bombers killed at least five people including three policemen near a bus station in Kampung Melayu — one of the suicide bombers, identified only as I.N.S., had links to another suicide bomber who detonated a bomb in Bandung in February. 

In the incident in February, a militant detonated a low-explosive bomb in the courtyard of a local government office in Cicendo, Bandung. The incident had no casualties and one of the perpetrators was shot by the police.

Police later in March arrested two other militants who were involved in that same attack. Investigations revealed that one of them, whom police identified only as A.M., had allegedly assembled the pressure-cooker bomb.

A.M. and the two other militants implicated in the Cicendo attack were allegedly part of Jemaah Ansharut Daulah, an umbrella organization on a United States State Department "terrorist" list that is estimated to have drawn hundreds of Islamic State sympathizers in Indonesia.

The group is led by Aman Abdurrahman, a cleric currently imprisoned on Nusakambangan Island at Cilacap, Central Java.

Police have named Aman as one of the masterminds behind the terrorist attack in Jalan Thamrin, Central Jakarta, in January last year, which resulted in the death of four people, including the attackers.

"There were documents about Islamic teachings, backpacks, shoes and two bayonets [at I.N.S.'s home]," he told the Jakarta Globe.

"We are still digging deeper into all of this, but it was found that the alleged perpetartor had known A.M.," Yusri added.

Police also said the bombs on Wednesday night, where twin blasts from pressure-cooker bombs occurred just minutes apart, were similar to that used in the Cicendo attack.

Yusri said police also searched the home of the second suspected suicide bomber's parents in Cimahi, Bandung, on Thursday and questioned his mother. Police identified him only as A.S.