Police in Spain have confirmed that the man they shot dead west of Barcelona Monday was the perpetrator of Thursday’s deadly van attack.

“We confirm that the man shot dead in #subirats is Younes Abouyaaqoub, author of the terrorist attack in #barcelona,” police tweeted on Monday, after earlier reporting that the man in the town of Subirats was wearing what appeared to be a suicide belt.

Catalan interior minister Joaquim Forn told Catalunya radio that “everything indicates” Younes Abouyaaqoub was behind the wheel of the van during Thursday’s Barcelona attack that killed 15 people.

Earlier, authorities said they had been searching for Abouyaaqoub as the last member of a 12-person cell still at large.

Police have arrested four of the suspects in the 12-man cell, while the rest were either killed by police or died in an explosion at a house on the day before the attack. Many of the suspects had connections to the northeastern town of Ripoll, one of the places where police have focused their investigation.

In a news conference Sunday, Spanish police reported that they found 120 gas canisters in a home in the town of Alcanar believed to be the bomb-making factory of the suspects in Thursday’s attacks. Enough materials were found to carry out “one or more attacks in Barcelona”, regional police chief Josep Lluis Trapero told reporters, revealing that traces of TATP explosive were also found.

The explosion Wednesday at that house left human remains in the rubble, and authorities were conducting DNA tests as part of the investigation.

In addition to Abouyaaqoub, authorities were also looking for an imam named Abdelbaki Es Satty, whom they believe may have radicalized some of those who carried out the attack in Barcelona and one later in the resort town of Cambrils that killed one person.

The Associated Press reports that neighbors said the vehicles used in the Cambrils and Barcelona attacks were seen at the Alcanar home prior to the blast.

Arrests may have prevented more attacks

Deakin University professor of global Islamic politics Greg Barton told VOA that Spain’s previous arrests of terrorism suspects could explain why it has not dealt with the same number of attacks as other countries in Europe such as France and Belgium in recent years.

“Spain is not immune from these problems, particularly Catalonia where there are links with northern Morocco,” Barton said. “But Spain up until now has been able to keep on top of the problem whereas France and Belgium have been struggling.”

Barton also said there does not seem to be any particular links between the influx of migrants to Europe and these attacks.

“The individuals being recruited have largely grown up in the countries where they’re recruited and they launch attacks in neighborhoods familiar to them,” he said.