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 family had been in Syria, where Islamic State until recently controlled large areas of the country, said the national head of police, Tito Karnavian.
According to police, Oepriarto was friends with the family that carried out Monday's police headquarters bombing and a third family, three members of which died when homemade bombs exploded in their apartment on Sunday night.More news: Woman slams into back of truck on Bangerter Highway
Police stand guard near the site of a blast at the Pentecost Church Central Surabaya (GPPS), in Surabaya, East Java, Indonesia May 13, 2018. Twenty-five people have died since Sunday, including 13 militants and their children.
Also on May 14, President Tran Dai Quang and Prime Minister Nguyen Xuan Phuc cabled messages of condolences to Indonesian President Joko Widodo over the recent terror attacks in Surabaya city of Indonesia. The top security minister, Wiranto, who uses one name, said the government will attempt to hasten passage of an updated anti-terrorism law that has languished in parliament.
But that changed on Sunday as a family of six - including girls aged nine and 12 - staged suicide bombings of three churches during morning services in Surabaya, killing 18 including the bombers. The mother, with her two daughters, attacked the Christian Church of Diponegoro, he said.More news: Salma Hayek speaks frankly about Harvey Weinstein and #MeToo at Cannes
Indonesia has been on high alert for attacks by homegrown militants, including some claimed by ISIS.
Karnavian said the father drove a bomb-laden auto into the city's Pentecostal church.
At least four people were killed and more than 40 wounded in the first attack at the Santa Maria Roman Catholic Church, officials said.More news: 5-year-old Colorado girl attacked, severely injured by black bear
Earlier on Tuesday, police searched the home of the family that bombed Surabaya's police headquarters and found unexploded bombs. It is also hard to detect it by X-ray, making it a popular type of explosives among terrorists.