Police in Jakarta say they believe that Indonesian national Bahrun Naim is behind Thursday's series of explosions and gun attacks. BBC Monitoring looks at what is known about this individual.
Bahrum Naim has been known to the authorities since at least 2010 and is currently thought to be in Syria with the so-called Islamic State (IS) group.
He has often been associated with East Indonesia Mujahidin Group (MIT) leader Abu Wardah Santoso, who has pledged allegiance to IS.
Naim is said to be the main liaison between MIT (which is based in Sulawesi) and IS in the Middle East.
A blog published under his name portrays him as a "freelance journalist" specialising in Muslim affairs, with a focus on politics, strategy and intelligence. The "about" section of the website says he was born in 1983.
Media reports say he previously worked as a computer technician and ran an internet cafe in Surakarta. He is believed to be from Pekalongan in Central Java.
In November 2010 he was arrested at his home in a village in Solo, on suspicion of involvement in a terrorism network. He was eventually convicted in June 2011 for illegal possession of ammunition under emergency legislation, but the court found insufficient evidence to pursue the terror charges.
During his detention, his family accused authorities of mistreating him.
A lawyer representing his family said: "We want proof of Naim's involvement in this case because since he was arrested his family has not received any explanation regarding his role. His family still doesn't know about his condition at present... This is not an arrest, but a kidnapping."
Indonesian intelligence agencies say that since relocating to Syria, Naim has been instrumental in recruiting and planning attacks against Indonesia.
A Chinese national from the Uighur ethnic group detained on terror charges just outside Jakarta last month is believed by the Indonesian authorities to have received funding from Naim.
Naim's blog celebrates attacks carried out by affiliates of IS, and offers encouragement and advice to those who have declared allegiance to the group. Many posts contain information on building explosives. Last August a post praising an attempted attack in Solo called on so-called "lone wolves" to "rise up against the Indonesian archipelago".
"Be lone wolves by whatever means you can," the post says. "Bamboo sticks, lighters, sand, knives, glass and even stones will demand you act out on your pledge of allegiance. The earth and sky will witness if you were honest in your pledge or not."
In a post dated 16 November 2015, he describes the Paris attacks of 13 November in which 130 people were killed as "astounding," and praises the perpetrators for their discipline, meticulous planning and willingness to sacrifice themselves.
"Why were the attacks inspirational?" the blog says. "First, a large number of people fell victim to the attack in Paris. Second, the attack was well planned in terms of target, timing and a courageous end to the attack. Only elite soldiers would use suicide vests rather than be captured or cornered."