Spain held a solemn religious ceremony attended by heads of state and government in Barcelona’s monumental Sagrada Familia basilica on Sunday to mourn the 14 persons killed in two terror attacks in the wealthy northeastern region of Catalonia.

The service, headed by King Felipe VI and Queen Letizia with Portugal President Marcelo Rebelo de Sousa and officiated by Cardinal Juan Jose Omella, took place as a police manhunt searched for the prime suspect in the Barcelona attack, Efe news agency reported.

The service mourned the 13 pedestrians killed in Barcelona’s Rambla boulevard on Thursday when a van driven by the suspected Islamist militant mowed them down, also leaving more than 100 people injured.

Hours later a car smashed into a group of pedestrians in the seaside resort town of Cambrils, killing a woman and injuring four other people.

Sources close to the investigation told Efe that police had begun a huge manhunt, concentrating on the area around the town of Manlleu, north of Barcelona, where police found one of three vans allegedly hired by members of the terror cell with the aim of launching the attacks.

Younes Abouyaaqoub, a resident of Ripoll who is now the main suspect in the Rambla attack, was reported to have frequented Manlleu. So investigators have focused on the surrounding area, given the possibility that someone might have given refuge to the fugitive.

Abouyaaqoud’s mother took part in a rally at Ripoll town hall square on Saturday and said she repudiated the attacks, asking her son to turn himself in.

She said it was difficult for her to believe that her son was a member of the terror cell.

A cousin, Fatima Abouyaaqoud, said she was convinced that a local imam, Abdelbaki Es Satty, had radicalised her relative and the other local youths allegedly involved in the attacks.

Investigators also raided and searched the imam’s home in Ripoll looking for evidence and DNA samples.

Experts want to be able to verify if the religious leader, who has disappeared, is one of those killed in an explosion that rocked a house in Alcanar on Wednesday when a makeshift bomb factory blew up destroying what investigators believe was the cell’s bomb arsenal and killing at least two suspected cell members.

Biological remains belonging to three people have so far been found in the rubble, according to sources consulted by Efe.

Explosive materials commonly used in Islamic terror attacks were also found in the rubble.

The regional Mossos d’Esquadra force are also searching for three cars related to the attacks, counter-terrorism investigators told Efe.

They are a 2002 gray Seat Ibiza with license plate 2538 BWK, a 2005 Volkswagen Touran registered as 819CDH06 and a French Renault Clio which could have registration number CW214SV.