Preventing the Catalonia attacks: what went wrong?

Could the terrorist attacks in Barcelona and Cambrils have been avoided? And if so, what — and who — failed? These are some of the questions on the table as news reports suggest that the mastermind behind the terrorist cell, the imam Abdelbaki Es Satty, had a history that pointed to his radicalization and, therefore, could have prompted the police into action that might have prevented the carnage that left 15 dead and more than a hundred injured.

Es Satty arrived in Ripoll, the Catalan town where most of the terrorists grew up, in 2015. According to the local Muslim community, his behavior raised no suspicions; he became the imam of a newly formed mosque and started preaching.

However, Es Satty had spent four years in prison between 2010 and 2014 for drug trafficking, information that neither the Muslim community nor the Catalan police claimed to know. During his time in prison, he met one of the jihadists responsible for the 2004 train bombings in Madrid that left 192 dead.