He was later identified as 22-year-old Younes Abouyaaqoub, who was alleged to be the man in photographs released Monday by Spanish newspaper, El País.
In the published photographs, he appeared to be casually walking away from Thursday's violent carnage he wrought on Las Ramblas, one of Barcelona's bustling boulevards where he ran over and killed 13 pedestrians.
CCTV footage caught the Moroccan fugitive on foot, wearing sunglasses and a striped shirt, in front of La Boquería, a covered marketplace just off of Las Ramblas.
The released footage proved to be crucial for the ensuing set of circumstances leading to his imminent fate on Monday.
Hours after the photographs were released, the police identified the suspect to be Abouyaaqoub and posted his images on social media. Time was of the essence as authorities feared he may have fled the border into France for another attack.
A manhunt encompassing Europe led authorities toward Subirats, a small town 20 miles West from Barcelona, after a woman identified the suspicious looking man wandering in the street as the fugitive she saw from the released photographs.
She immediately contacted local authorities, and police finally tracked down and confronted the jihadist.
Wearing an explosive suicide belt that turned out to be a ruse, Abouyaaqoub reportedly yelled, "Allahu akbar,” before police shot and killed him.
In addition to killing 13 people with his van on Las Ramblas, Abouyaaqoub also allegedly stabbed driver Pau Perez to death and hijacked his car after the CCTV footage caught him fleeing on foot.
Hours later, five of the Moroccan national's associates killed a woman in a related attack in the coastal resort of Cambrils, bringing the death toll to 15.
The five attackers responsible for murdering the woman in Cambrils were shot and killed by police on the scene.
Abouyaaqoub was the 12th suspect linked to the Spain attacks.
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