AUDIE CORNISH, HOST:
One thread of the investigation into the Paris terrorist attacks has led to Spain. The gunman who murdered four people in a kosher supermarket is believed to have traveled to Madrid just before the attacks. Police are trying to figure out where he stayed and who he met, but, as Lauren Frayer reports, news of his presence there has upset many Muslims in the Spanish capital.
LAUREN FRAYER, BYLINE: This is Madrid's biggest mosque - a sprawling, white, marble complex built by Saudi Arabia and nicknamed for the M30 highway over which its minaret towers.
UNIDENTIFIED IMAM: (Reciting surah in foreign language).
FRAYER: Inside, an Imam recites a peaceful surah from the Quran. But people here are shaken. One of the Paris gunmen, Amedy Coulibaly, visited Madrid in the days before his attack. Muslims here worry he may have prayed alongside them.
SAMI ELMUSHTAWI: (Speaking Spanish).
FRAYER: "I don't like to think a violent person could have been in our mosque," says its director, Sami Elmushtawi. "But, at the same time, our doors are open to all. I won't add security. I don't want people to panic," he says. Coulibaly is believed to have spent New Year's in Madrid with his partner before she flew to Turkey and he drove home to Paris, where he killed four shoppers at a kosher supermarket January 9 and then died in a police raid. Spanish police are trying to figure out where Coulibaly stayed in Madrid. They can't find any hotel reservation and whether he had any local help.
JUAN FERRARO: He was here and he might have some friends. But, you know, we are 40 - almost 47 million Spanish people. It's very difficult.
FRAYER: Human rights lawyer, Juan Ferraro, was also visiting the mosque. In tense times, he acts as an informal liaison between the Muslim community and law enforcement.
FERRARO: If they gather in the cafeteria of some mosque, that's normal because what the terrorists want is to gather in places where there's no control.
FRAYER: Fifteen people were arrested last June for allegedly using this mosque's cafeteria as a recruiting hub for ISIS, to which Coulibaly had pledged allegiance. None of the worshipers I met said they knew anything about the cafeteria plot or of Coulibaly's movements in Madrid. But some, like Rodrigo Rodriguez, a Spanish convert to Islam, certainly have opinions about him.
RODRIGO RODRIGUEZ: What I think is that that guy - he hasn't even read the Quran. I think that guy - he doesn't even make his daily five prayers. I think that guy is an ignorant. He's a murderer, and people shouldn't give a damn about if he' a Muslim or whatever. He's just a madman with a gun.
FRAYER: Muslims are angry that, after the cafeteria arrests, Coulibaly's Madrid sojourn might cast further suspicion on them. Mosques across Spain were vandalized in the days after the Paris siege. Meanwhile, amid arrests of suspected militants across Europe, police say a suspect who escaped capture in Belgium, an 18-year-old Dutch Muslim, may have also fled to Spain.
This country's al-Qaida cells are thought to have been dismantled 10 years ago, after the Madrid train bombings that killed nearly 200 people. But people who study radicalization in Spain say sleeper cells may be reactivating and may provide a possible haven for militants. For NPR News, I'm Lauren Frayer in Madrid. Transcript provided by NPR, Copyright NPR.
