Five members of the cell were shot dead by police after they rammed a car into a group of pedestrians in Cambrils, killing a woman and injuring six others in the early hours of Friday morning. A bomb disposal robot was dispatched to approach him, police said.
Authorities had previously confirmed that the suspects, all of Moroccan origin, had been planning a far larger attack than the one that took place.
On Sunday, King Felipe VI, Queen Letizia, Spanish Prime Minister Mariano Rajoy and other officials attended a solemn Mass at Barcelona's Sagrada Familia basilica for the victims of the attacks.
Authorities are looking for Younes Abouyaaqoub, a 22-year-old they believe was behind the wheel of a van which left a trail of dead and injured on Barcelona's famed boulevard.
Police also released more images of Abouyaaqoub, and appealed for help in finding him. Police say Abouyaaqoub was wearing what appeared to be a belt of explosives when he was shot down.
Cristiano Pecchi, an Italian tourist, first heard gunfire at around 4pm. On Saturday, police raided his apartment.
"But we have said that we were opening up the range of relations in the international field and this will develop in the coming weeks", he said, adding that the operation was not closed.
On Monday, authorities said that while fleeing the scene of his initial attack, Abouyaaqoub hijacked a car and stabbed to death its occupant.
Police say the cell consisted of 12 men, all with connections to the northern town of Ripoll.
However the two bodies found in the rubble have yet to be formally identified.
The news came four days after the attack in the city in which a van swerving through the crowded Las Ramblas promenade killed 13 people.
Regional authorities said Monday that 50 people are still hospitalized from both attacks, nine of them in critical condition.
He passes people rushing from Las Ramblas.
At the bomb house, police also said they had found remote-controlled detonators.
Locals familiar with Es Satty said the imam showed no signs of extremism leading up to the attacks. Belgium has suffered several Islamist attacks and Vilvoorde has been a centre of Islamic radicalism.
The van driver, Abouyaaqoub, began showing more religiously conservative behaviour over the past year, said relatives in his native Morocco.
"Everything points to that", he added.
Moussa Oukabir, aged 17 or 18, Said Aallaa, 19, and Mohamed Hychami, 24, were among those killed by officers.