Subirats - Four suspects detained during the investigation into the deadly Catalonia attacks will appear before a judge for the first time on Tuesday, after the eight other members of the jihadist terror cell were killed."The 12 principal targets are detained or dead," the Catalan police tweeted on Monday at around 20:00 (18:00 GMT).On Monday, Spanish police shot dead Barcelona terror suspect Younes Abouyaaqoub in a dramatic end to a massive manhunt for the Moroccan national who was wearing a fake suicide belt and shouting "Allahu Akbar" (God is Greatest) when he was killed.The Moroccan was the last remaining member of a 12-man cell suspected of plotting last week's deadly vehicle rampages in Barcelona and the seaside resort of Cambrils that were claimed by the Islamic State organisation (IS) - its first in Spain.Four men have been detained, and the rest have been killed, either by police or in an explosion believed to have been accidentally detonated by the suspects themselves in their bomb factory in the seaside town of Alcanar.Imam killedAfter five days in detention, the four remaining suspects will appear before a judge on Tuesday in Madrid at a special tribunal for terrorism. The judge will then decide whether they are to be charged.Among those killed in the explosion was a Moroccan imam at the heart of the cell, Abdelbaki Es Satty, Catalan police chief Josep Lluis Trapero confirmed on Monday.Four days after his van rampage on the tourist-packed Las Ramblas boulevard, police gunned down the 22-year-old Abouyaaqoub in the village about 60km west of Barcelona after receiving multiple tip-offs on sightings of the fugitive.Arnau Gomez, who lives about a kilometre away from where the suspect was shot, described the village of 300 people as being an ideal hideout as "it is far from everything"."In the hills there are many homes of seasonal workers, it's easy to hide," he said.In Abouyaaqoub's hometown Ripoll, where many of the suspects grew up or lived, Moroccan factory worker Hassan Azzidi said he was "happy and sad all at once" that the suspect had been gunned down."This had to end, because we're living as if in a war, but at the same time, someone brainwashed such a young boy," he said.Authorities earlier on Monday raised the death toll to 15, confirming that Pau Perez, a 34-year-old man found stabbed to death in a Ford Focus outside Barcelona on Friday, was killed by Abouyaaqoub.Terror cellInvestigators believe that Abouyaaqoub had hijacked the car from the victim to make his getaway.The police had fired at the car as it forced its way through a checkpoint shortly after the Barcelona carnage, and later found Perez in the vehicle.Investigators seeking to unravel the terror cell had homed in on the small border town of Ripoll at the foot of the Pyrenees mountains.Satty, aged in his 40s, has also come under scrutiny as he is believed to have radicalised youths in Ripoll.Police said the imam had spent time in prison and had once been in contact with a suspect wanted on terrorism charges, but was never charged with terror-related incidents.In Belgium, the mayor of the Vilvorde region said that Satty spent time in the Brussels suburb of Machelen - next to the city's airport - between January and March 2016.In the Moroccan town of M'rirt, relatives of Abouyaaqoub have accused the imam of radicalising the young man as well as his brother Houssein."Over the last two years, Younes and Houssein began to radicalise under the influence of this imam," their grandfather said.Fake explosive beltsThe suspected jihadists had been preparing bombs for "one or more attacks in Barcelona", Trapero said on Sunday, revealing that 120 gas canisters and traces of TATP - a homemade explosive that is an IS hallmark - had been found at their bomb factory.The accidental explosion in the house in Alcanar, south of Barcelona, may have forced the suspects to modify their plans.Instead, they used a vehicle to smash into crowds on Barcelona's Las Ramblas boulevard, killing 13 people and injuring about 100.Several hours later, a similar attack in Cambrils left one woman dead. Police shot dead the five attackers, some of whom were wearing fake explosive belts and carrying knives.Hundreds of Muslims rallied Monday at Las Ramblas, holding slogans like "No to terrorism" and "We are Muslims, not terrorists".