The four suspected members of a terror cell — the only members believed to be alive — appeared in a Madrid court Tuesday in connection with the attacks in Spain last week that killed 15 people.The hearing took place behind closed doors. But numerous Spanish and international news outlets say multiple suspects testified that a former imam was the mastermind of a failed plot to use explosives in a large-scale attack.Suspect Mohamed Houli Chemlal testified that the initial targets included monuments in Barcelona, including the famed Sagrada Familia cathedral, the BBC reported, citing judicial sources.Authorities say the imam, Abdelbaki Es Satty, was killed in an explosion in the city of Alcanar the day before the vehicle attacks in Barcelona and the resort town of Cambrils. As The Two-Way has reported, "authorities believe the explosion was the result of a failed attempt to make a bomb and that the deadly vehicle attacks in Barcelona and Cambrils were a fallback plot."The Spanish newspaper El Pais reports that Es Satty had planned to immolate himself.Es Satty was an imam in Ripoll, a small town in northeastern Spain, and is believed to have recruited most of the suspects in what is believed to be a 12-person cell.NPR's Frank Langfitt spoke to Ali Yassine, the president of a local mosque that hired Es Satty. "Everything he did was ordinary. He never said anything strange," Yassine said. "He didn't have a radical message. Everything was normal."But El Pais quoted a cousin of two of the suspects as saying that Es Satty "had been meeting with some [of the suspects] outside the mosque for at least a year."The cousin told the newspaper that the imam would meet them for hours at a time inside a parked van. "If someone walked past, they stopped talking and started looking at their mobiles," the cousin said.The prosecutor's office requested that the four suspects be remanded into custody without bail. But according to The Associated Press, National Court Judge Fernando Andreu "ordered two of the four surviving suspects in last week's extremist attacks in Spain held without bail, another detained for 72 more hours and one freed."Another suspect who testified Tuesday, Driss Oukabir, told the court that he rented the van that was used to run over people in Barcelona. But he said he was under the impression that it would be used for a move, judicial sources tell El Pais.Oukabir had previously said that his brother stole his documents in order to rent the vehicle.The two additional suspects have been identified as Mohamed Aallaa and Salah El Karib, according to El Pais. The attacks last Thursday started on Barcelona's Las Ramblas promenade, where authorities say a van killed 13 people. Authorities say they believe the driver is named Younes Abouyaaqoub. As The Two-Way reported: