The Islamic State (IS) group took responsibility for the bloodshed of August 17th-18th, when pedestrians were mown down by a van in Barcelona and others were attacked at a nearby seaside town as Europe reeled from a string of jihadist attacks.
Since the trial began more than three months ago at a branch of the National Court near Madrid, more than 200 witnesses have testified, with the judges now meeting to weigh their sentence in a process which could take weeks.
Although the six perpetrators were shot dead by police, many questions remained, with investigators and victims hoping the trial would shed light on how the violence unfolded, which also left 140 people wounded.
While none of the trio are charged with carrying out the attacks, they are accused of helping the jihadists, one of whom ran down pedestrians on Barcelona's Las Ramblas on a busy Thursday, killing 14. The driver then killed another person before being shot dead days later.
Hours later, just after 1:00 am on Friday morning, five others rammed pedestrians in Cambrils, 100 kilometres (60 miles) further south, and fatally stabbed a woman before being shot dead by police.
Mohamed Houli Chemlal and Driss Oukabir are accused of belonging to a jihadist group, manufacturing and possessing explosives and conspiracy to wreak havoc.
If convicted, prosecutors want them jailed for 41 and 36 years respectively. Said Ben Iazza is on trial for collaborating with the cell, with prosecutors calling for an eight-year sentence.
'I don't support IS extremism'
All three have followed the trial from a thick glass booth, carefully separated and wearing masks because of the coronavirus pandemic.
“I did not know what was going to happen in Barcelona, nor in Cambrils” and “I don't support the extremist views of Daesh,” Chemlal, 23, said in his final statement on Wednesday, using the Arabic acronym for IS.
During the investigation, Chemlal admitted the initial plan was to hit targets like Barcelona's Sagrada Familia basilica, with police finding documents relating to the city's Camp Nou football stadium and the Eiffel Tower.
But an accidental explosion on August 16th at a house where they had been preparing explosives, which killed the group's spiritual leader and injured Chemlal, forced the cell to hurriedly improvise the weekend attacks.
The van used in the Ramblas attack was rented by Oukabir, who during the trial insisted he was not part of the cell and was not religious. “It never crossed my mind that this would happen,” the 31-year-old said in his final statement, adding that if he had known “he would have tried to stop it”.
Experts testified that Oukabir was fully aware why the van had been hired, saying that both he and Chemlal “were involved in the events”.