From the Washington Post:

Stephane Medot knows a thing or two about Belgian prisons. He spent 10 years in them. Arrested for carrying out more than a dozen armed bank robberies, the stocky, bald-headed Medot moved from prison to prison, from one cell of his own to another, until he served out his time.

Along the way, he got a front-row seat in a prison system that has become a breeding ground for violent Muslim extremists. Many of those involved in the Paris and Brussels attacks first did short stints behind bars for relatively petty crimes. And there these wayward young people met proselytizers and appear to have acquired a new, lethal sense of purpose.

A Belgian prison is where Abdelhamid Abaaoud, who helped plan the Paris attacks and who was killed in a police raid in November, met Salah Abdeslam, an alleged Paris attacker who was captured in Brussels this month. Salah’s brother Brahim, who blew himself up in Paris, also served time.

Two of the suicide bombers in the Brussels attacks last week, brothers Ibrahim and Khalid el-Bakraoui, had spent time in Belgian prisons for violent offenses that included armed robbery and carjacking.

Medot, now 37, said that from prison to prison, the routine he witnessed was similar. Proselytizing prisoners used exercise hours and small windows in their cells to swap news, copies of the Koran and small favors such as illicit cellphones. Gradually, they won over impressionable youths and taught them to stop drinking and start thinking about perceived injustices such as the invasion of Iraq, the plight of Palestinians or the treatment of their own immigrant families.

The prison guards, who could not understand Arabic, had a “laissez-faire attitude,” he said, and did nothing to stop the pulsating music or political discussions.

“If you’re not a Muslim, you feel the need to adapt to the rules,” said Medot, who is not Muslim. When the hour for prayer arrived, everyone was asked to turn off televisions so as not to disturb the faithful.