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Police could not confirm if Abouyaaqoub was the suspected driver or had some other role.
Four suspects were earlier arrested, one in Alcanar, southwest of Barcelona, and three in Ripoll.
Spain's Interior Minister Juan Ignacio Zoido told reporters the government considered the cell behind the attack to be successfully "dismantled." He added that the terror threat level would remain at four, meaning the threat is "high," rather than increasing it to level five, which means an attack is believed to be imminent. He said security would be upped around tourist hot-spots.
Thursday’s van-rampage was one of three incidents in northeast Spain that officials believe are connected.
Hours after the downtown van ramming, an Audi A3 plowed into pedestrians in the popular seaside resort of Cambrils, 60 miles south of Barcelona, killing one person and injuring six.
Minutes later, police shot dead the five attackers who were wearing fake bomb belts. Police on Saturday named three of those attackers as Moussa Oukabir, Said Aallaa and Mohamed Hychami.
Also believed to be connected is a house explosion that killed one person Wednesday night in the town of Alcanar, around 100 miles to the southwest. Police believe the property was used to plan the attacks, and that the accidental explosion prevented a far deadlier attack, according to the Associated Press. Spanish police said Saturday they would carry out controlled explosions at the property.
Two senior U.S. intelligence officials briefed on Spain's investigation into the terror attack told NBC News the attackers had planned to use propane and butane cylinders to build a large truck bomb in Barcelona.
Saphora Smith is a London-based reporter for NBC News Digital.