Barcelona (CNN) Spanish authorities on Monday shot and killed the suspected driver of the van that plowed into crowds last week in Barcelona, according to Catalan police.

A robot was sent to remove the belt from before officers were cleared to approach and make a positive identification, in case the belt turned out to be real. The suspect also had knives in his possession when he was shot, said José Lluís Trapero, head of Catalan police.

A woman alerted authorities after seeing police photos of Abouyaaqoub and becoming suspicious that the man was wearing long sleeves when it was about 85 degrees (30 degrees Celsius) outside, he said. Witness accounts suggest Abouyaaqoub was alone when police arrived, Trapero said.

Police killed Abouyaaqoub in a rural area, sparsely populated and surrounded by pine trees. After the gunfire, a police helicopter circled overhead. Several police officers and squad cars were nearby, but few onlookers.

Abouyaaqoub, a 22-year-old Moroccan national, is alleged to have been the sole driver of the van used to kill 13 people Thursday on Las Ramblas, a thoroughfare that's a popular tourist destination. More than 100 others were injured.

The Spanish Interior Ministry released this image of suspect Younes Abouyaaqoub.

Investigators said Abouyaaqoub fled the scene of Thursday's attack on foot and hijacked a car to escape. Abouyaaqoub allegedly stabbed the owner of the car, Pau Perez, as he parked the vehicle, and drove off with his body inside the car.

Police fired on the car after it rammed through a checkpoint, but Abouyaaqoub was able to flee a second time. Perez was found dead in the vehicle, making him the 15th victim of the attacks in Barcelona and the Catalan town of Cambrils, where one woman died early Friday when attackers drove into pedestrians there.

Police conduct more raids

Speaking to local radio, Joaquim Forn, the Catalan interior minister, said all evidence pointed to Abouyaaqoub being the sole driver and that security services were working with other agencies around Europe to find him.

Police carried out more raids overnight at homes in the town of Ripoll, north of Barcelona, where eight of the 12 suspects lived, Forn said.

Abouyaaqoub was one of 12 terror suspects linked to the Spain attacks. Authorities have said none had any previous link to terror activities.

On Saturday, Spanish Interior Minister Juan Ignacio Zoida said the terror cell believed to be responsible for the attack had been "completely dismantled."

Meanwhile, Catalan police said in a series of tweets that four suspected terrorists have been detained, and eight have been killed, "but that does not mean that the investigation is over. We keep working."

Confirmamos la muerte de Younes Abouyaaqoub, abatido en #Subirats / We confirm the death of Younes Abouyaaqoub shot in #Subirats https://t.co/ZzpCBFZOGC — Mossos (@mossos) August 21, 2017

So far there are 4 detainees and 8 suspected dead terrorists regarding the attacks of #Barcelona and #Cambrils — Mossos (@mossos) August 21, 2017

The 12 initial targets regarding the attacks are dead or detained but that does not mean that the investigation is over. We keep working — Mossos (@mossos) August 21, 2017

Imam link

The investigation has focused on a property in Alcanar, suspected of being used as a base to make explosives that could have caused even more devastating attacks had they not blown up prematurely Wednesday before the attacks.

Police believe Muslim cleric Abdelbakir El-Satty is among those who died in the Alcanar blast.

Photos: Terror attacks in Spain A makeshift memorial pays tribute to those who were killed in a terror attack in Barcelona, Spain, on Thursday, August 17. A van rammed into a crowd of people near the popular tourist area of Las Ramblas. Early the next morning, a group of five attackers drove into pedestrians in the Spanish town of Cambrils, about 75 miles south of Barcelona. Hide Caption 1 of 19 Photos: Terror attacks in Spain Two women cry at the street memorial in Barcelona on Friday, August 18. Hide Caption 2 of 19 Photos: Terror attacks in Spain A man embraces a police officer in Cambrils on August 18. Earlier in the day, officers had engaged in a shootout with five attackers who drove a car into several pedestrians. All five were shot dead by police, four of them by one officer, police said. Hide Caption 3 of 19 Photos: Terror attacks in Spain Pigeons fly over a Barcelona crowd that gathered for a minute of silence on August 18. Hide Caption 4 of 19 Photos: Terror attacks in Spain Spain's King Felipe VI joins other officials in observing a minute of silence in Barcelona's Plaça de Catalunya. Hide Caption 5 of 19 Photos: Terror attacks in Spain Police officers investigate a car in Cambrils. Hide Caption 6 of 19 Photos: Terror attacks in Spain The van that plowed into the crowd in Barcelona is towed away from Las Ramblas on August 18. Hide Caption 7 of 19 Photos: Terror attacks in Spain Police officers check the area after towing away the van. Hide Caption 8 of 19 Photos: Terror attacks in Spain Police accompany clients of a store outside a cordoned off-area of Barcelona. Las Ramblas is especially crowded in the summer, the height of tourist season. The promenade passes by kiosks, flower sellers, cafes and bars. Hide Caption 9 of 19 Photos: Terror attacks in Spain Police officers work at the scene in Cambrils. Hide Caption 10 of 19 Photos: Terror attacks in Spain Police check people's identities as they clear Las Ramblas on August 17. Hide Caption 11 of 19 Photos: Terror attacks in Spain People evacuate an area of Barcelona on August 17. Hide Caption 12 of 19 Photos: Terror attacks in Spain Medics and police tend to injured people near the scene of the attack in Barcelona. Hide Caption 13 of 19 Photos: Terror attacks in Spain A woman cries as she speaks on her phone in Barcelona on August 17. Hide Caption 14 of 19 Photos: Terror attacks in Spain People react after the incident in Barcelona. Hide Caption 15 of 19 Photos: Terror attacks in Spain A police officer asks people to move back in Barcelona. Hide Caption 16 of 19 Photos: Terror attacks in Spain An injured person is carried by police in Barcelona. Hide Caption 17 of 19 Photos: Terror attacks in Spain People flee the scene after the attack at Las Ramblas. Hide Caption 18 of 19 Photos: Terror attacks in Spain The Catalan emergency services urged people via Twitter to avoid going out or undertaking any other type of movement that is not "strictly necessary." Hide Caption 19 of 19

The cleric once served a jail sentence for drug trafficking in the eastern Spanish province of Castellon, not in Catalonia, Catalan Justice Minister Carles Mundó i Blanch said.

Some Spanish media reported he shared a jail cell with one of the terrorists involved in the 2004 Madrid bombings that killed at least 191 people and left hundreds injured.

Responding to those reports, Blanch said, "We are not aware that this person had any communication with any inmate in any prison in Catalonia. He finished his sentence and went free."

Bulldozer clears rubble in Alcanar

In Alcanar on Sunday, explosives experts brought in a bulldozer to clear rubble before conducting a number of controlled detonations at the site. The remains of two people have been found there.

The debris of a house in the village of Alcanar may hold clues about the terror cell's plans.

So far, police have discovered the remains of more than 100 gas canisters on the site.

Alcanar Vice Mayor Jordi Bort told CNN the house belonged to a bank and the group had been squatting there illegally without its knowledge.

The town is home to a mix of residents and others who spend holidays or weekends here, he said. Neighbors said they did not suspect any wrongdoing at the property.

The septic tank of the house, which had only one floor, was used as storage for the tanks and explosives, Bort said.

A source briefed on the investigation said a preliminary assessment indicated there were traces of the powerful explosive TATP in the rubble.

TATP is made by adding acid to a mixture of acetone and hydrogen peroxide solution and can easily result in accidental detonation if mistakes occur in the preparation.