KELLY MCEVERS, HOST:
Nearly all of the men implicated in last week's attack in Belgium and the November rampage in Paris have something in common. They are ex-convicts. The two brothers thought to have blown themselves up at the airport and metro station in Brussels spent time in prison - one for bank robbery, the other for carjacking. They are a new breed of violent jihadi, and they're particularly receptive to ISIS's message. NPR's Dina Temple-Raston has this report from Brussels.
DINA TEMPLE-RASTON, BYLINE: Lantin Prison, a minimum-security detention facility about 10 minutes from downtown Liege, houses about 960 prisoners. We turn onto a long asphalt road.
This is not a big prison. It doesn't seem to be.
PHILIPPE MASSAY: That's a big prison for Belgium.
TEMPLE-RASTON: Is it?
MASSAY: Maybe for the United States, it's a small one. But here for Belgium, it's a big one, yes.
TEMPLE-RASTON: Philippe Massay has been a guard at Lantin for the past five years.
MASSAY: Here you have the main entry.
TEMPLE-RASTON: That's where he reports to work every day.
MASSAY: This big block, yes, of eighth floor - that's the maison d'arret.
TEMPLE-RASTON: It looks like a public housing bloc with bars on the windows. It's where prisoners await trial or sentencing. And at Lantin Prison and in Belgium generally, these units are overflowing.
Officials close to the Brussels investigation believe Ibrahim el-Bakraoui started his transformation from local hood to violent jihadist in a prison unit just like this one. Massay says the maison d'arret was designed for prisoners with short stays, so there were few organized programs to keep inmates occupied. As a result, that early chapter of incarceration is when prisoners are considered particularly vulnerable.
So is this why more people may be radicalized when they're waiting for trial as opposed to after trial?
MASSAY: Yes, that's possible.
TEMPLE-RASTON: So there's something you should know about Philippe Massay. Before he became a prison guard, Massay had a long career as a social worker, and it shows. He has a gentle, empathetic quality. A few years ago, he got his master's in criminology focused on terrorism and radicalization, so he has special understanding of what he's witnessing at work.
MASSAY: Yes, I've seen radicalization in prison, sure.
TEMPLE-RASTON: He says a prisoner on his floor was a member of al-Qaida's arm in Somalia.
MASSAY: You have been charged for terrorism. And I speaks often with him, and I know that's a real radical.
TEMPLE-RASTON: And Massay has watched him try to radicalize others.
MASSAY: Come near this prisoner, and he said, OK, you are punished; can I help you; can I give you some advice? And that's the way he took over the mind of the people.
TEMPLE-RASTON: Prison guards are supposed to report incidents like this, but unlike Massay, his coworkers haven't been trained. He says they can't tell the difference between someone who's radicalizing and someone who's merely rediscovering their religion. Delivery of a Koran, for example, can get someone written up.
And to prisoners, that smacks of discrimination. They are punished, essentially, for being Muslim. And studies show more than any other single factor, discrimination - not poverty, as some suggest - has a direct link with terrorism.
Luk Vervaat taught English and Dutch in Belgium prisons for years, and now he's become an activist for prisoner reform. We met him in front of the memorial to the victims of last week's attacks in downtown Brussels. He agrees that discrimination is at the core of Belgium's radicalization problem. With few jobs, many people in minority communities turn to black-market cigarette sales or drug deals.
Salah Abdeslam, the man who is to be extradited to France soon for his role in the Paris attacks, and his brother, one of the Paris bombers, both dealt drugs. They ended up in prison where they met some of the people behind the Paris attacks. Vervaat says it's a vicious circle.
LUK VERVAAT: If you have an overcrowding, if you have the conditions where they bloc up people like they do, You create a collective amongst the people involved but also an association with the oppression elsewhere.
TEMPLE-RASTON: In other words, when ISIS calls for recruits here in Belgium, they have a receptive audience.
VERVAAT: There's a link between all these elements that creates a possibility of radicalization. That's clear.
TEMPLE-RASTON: We asked the Ministry of Justice to discuss radicalization in Belgian prisons, but they declined to speak to us. Clearly, though, prisons in Belgium have become a gateway to ISIS. Soon after Ibrahim el-Bakraoui, the airport bomber, was released the first time, Turkish authorities discovered him on the border with Syria. Exactly what happened next is less clear, but he ended up in Brussels having failed to join ISIS.
TAOUFIK AMZILE: People who are following ISIS are also looking for a recognition.
TEMPLE-RASTON: That's Taoufik Amzile, a business leader in the Moroccan community here. He says in some communities, prison has become a kind of rite of passage.
AMZILE: Going there and being recognized as, OK, I am something that counts for the society because I am a danger - and then it gives them a status. So going to prison is sometimes - and you go out, then you have a kind of stamp, a quality label that's, OK, you count. And this is sometimes what they look for.
TEMPLE-RASTON: The concern is that ISIS has become a rite of passage, too. Young men with prison records know if they join ISIS, their criminal skills are appreciated. And they couldn't be appreciated more than if they returned home to attack Europe. Dina Temple-Raston, NPR News, Brussels.