The officers brandished the number plate from one of two motorcycles that had been turned into a bomb that day to snuff out 13 lives and wound dozens.
Police spokesman Frans Barung Mangera said: "The husband drove the vehicle, an Avanza, that contained explosives and rammed it into the gate in front of that church".
The police headquarters in the city of Surabaya has been the target of the latest suicide bomb attack, injuring police officers and civilians.
Indonesian President Joko "Jokowi" Widodo condemned the attacks as "barbaric" and vowed that authorities would root out and destroy Islamic militant networks. Still another attacker was seen in footage speeding on a scooter toward a church before an explosion. The mother and her 17-year-old daughter died in an attack in the Surabaya suburb of Sidoarjo shortly after the father detonated an explosive prematurely.
ISIS, from which the recent attackers reportedly took their cues, has always understood - more than previous terror groups - the power of using provocative violence, Barton said. "One of them was a little kid", national police chief Tito Karnavian said.
During Sunday morning's attacks, one suicide bomber appeared to have been disguised as a churchgoer.
The Islamic State has claimed responsibility for the attacks, describing each of the bombings as a "martyrdom" operation carried out by three modes of attack: a vehicle bomb, a suicide vest and a motorcycle-borne bomb.
Officials said police, backed by military forces, would increase security across the country.
SB: #7 Georgia to Host NCAA Athens Regional
Illinois-Chicago earned an automatic bid to the NCAA field by winning the Horizon League Tournament for the second year in a row. It's the second time teh Ducks, who won the Pac-12 title for the fifth time in six seasons, received the top seed (2014).
A spokesperson for the country's intelligence agency said Sunday's bombings were suspected to have been carried out by an ISIL-inspired group, Jemaah Ansharut Daulah (JAD).
He said that the family's patriarch, who was the "main ideologue" and a key influence over the family implicated in Sunday's church bombing was apprehended in Turkey and deported back home. Other attacks killed 22 people on the island of Sulawesi in May 2005, and 20 in Bali later that year. The second family was also linked to JAD.
The police raid brings to 13 the number of suspected militants belonging to three families who carried out five separate attacks.
At Surabaya Centre Pentecostal Church, Futrianto then drove his auto onto the church grounds and detonated explosives.
"To them, the state of Indonesia does not exist - only the caliphate of (ISIS leader) Abu Bakr al-Baghdadi is legitimate", said Mr Ridlwan, adding JAD members are told to be always prepared to strike - training, casing targets, assembling bombs - when the opportunity arises.
"There has been an explosion, we don't know exactly what happened", he said.
Aman Abdurrahman is now on trial for several bombings in the country in recent years, including the deadly January 2016 attack in Jalan M.H. Thamrin, Central Jakarta.
"We've also seen children involved in executing political prisoners, and there's always been an appetite in Islamic State to use women and children".