Surabaya police spokesman Frans Barung Mangera said the militant died in a shootout in a Surabaya neighbourhood with counterterrorism police, who had tried to arrest him over possible involvement in the attacks that killed at least 13 people.
Futrianto was reported to have dropped off his wife, Puji Kuswati, and their two daughters, ages 9 and 12, at Diponegoro Indonesian Christian Church in Surabaya, East Java.
Following the attacks, police uncovered bombs at other churches and on Monday another family group of suicide bombers targeted a police station.
The flurry of bombings raised concerns that previously beaten-down militant networks in the world's most populous Muslim-majority nation have been reinvigorated by the return of some of the estimated 1,100 Indonesians who went to fight with the Islamic State group in Syria.
THE Department of Foreign Affairs says it "continues to receive information" terrorists are planning fresh attacks in Indonesia and has warned Australians to take particular care in the country over the next few weeks.
The use of children in the attacks has been particularly horrifying to people.
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In Surabaya, Indonesia, a family has involved an 8-year-old girl, in a suicide bomb attack in order to settle scores with an opposition. Jemaah Islamiyah, the al-Qaida affiliated network responsible for the Bali attacks, was obliterated by a sustained crackdown on militants by Indonesia's counterterrorism police with USA and Australian support.
Separately on Sunday, three members of another family were killed when homemade bombs exploded at an apartment in Sidoarjo, a town bordering Surabaya, police said.
Terrorist in Indonesia made police their main target after a number of their leaders and fellow terrorist fighters were arrested or killed by special anti terrorist police squad.
"What happened is their parents indoctrinated the children", said Arifin, "So when the mother asked them to wear the waist bombs they did it".
At Surabaya Centre Pentecostal Church, Futrianto then drove his vehicle onto the church grounds and detonated explosives.
Elsewhere family and friends mourned the deaths of the 12 people killed in the church blasts.
"According to police, on Sunday morning, "Two young boys aged 16 and 18 rode a motorcycle into a church courtyard and detonated their explosives".