Updated at 11:10 a.m. ET
A Catholic Mass was held in Barcelona on Sunday to honor the victims of last week's terror attacks, as authorities continued a manhunt for at least one suspect in the killings of 14 people along Spain's northeast Mediterranean coast.
NPR's Soraya Sarhaddi Nelson reports from Barcelona that thousands attended the Mass, held in Spanish and Catalan languages, at the city's iconic Sagrada Familia Basilica. Among those present were King Felipe and Queen Letizia.
Auxiliary Bishop Sebastia Taltavull called for peace and coexistence and prayed for a quick recovery for the more than 100 people injured on Thursday when a van plowed into pedestrians on Barcelona's popular Las Ramblas promenade, killing 13. Another person was killed hours later in a similar attack farther south on the coast in Cambrils.
Spanish authorities on Sunday confirmed that a missing 7-year-old boy was among the dead from the Barcelona attack.
Meanwhile, authorities were continuing to search for Younes Abouyaaqoub, 22, who is suspected of driving the van in Barcelona.
Catalonia's Chief of Police Josep Lluis Trapero said he could not rule out the possibility that Abouyaaqoub had crossed over the border to France.
"We don't have any specific information on this but it cannot be ruled out," Trapero told a news conference in Barcelona. He said border checks were beefed up immediately after the attacks.
Trapero said authorities believe there were 12 members of the cell that carried out the attacks, but that none of them had any previous links to terrorism.
NPR's Nelson tells Weekend Edition Sunday that police believe Muslim cleric Abdelbaki Es Satty "recruited and radicalized the suspected driver, as well as the other youths" in the mostly Moroccan-born cell.
She said they believe Es Satty may have been killed in an explosion at a house in Alcanar that the cell had used as a base and a bomb-making factory. The explosion on Wednesday, a day before the attacks, is believed to have been the result of a faulty bomb.
"Our thesis is that the group had planned one or more attacks with explosives in the city of Barcelona," Trapero told reporters.
NPR's Frank Langfitt, reporting from Ripoll, the town where Es Satty had lived, said the imam arrived in the tourist town of about 10,000 people in 2015. Most of the members in the cell were also from Ripoll.
"Es Satty's apartment mate told NPR this morning that the imam cleaned out his bedroom here last Tuesday," a day before the house explosion, Langfitt reports for Weekend Edition Sunday.
Police were trying to obtain DNA from the house explosion in hopes of determining whether Es Satty was killed there, according to Spanish media.