The imam from the small Catalan town of Ripoll who headed the jihadist cell behind the terrorist attacks in Barcelona and Cambrils in mid-August in which 16 people died, was no stranger to Spain’s security forces. Apart from having been investigated as part of the Chacal operation into Islamic jihadism – carried out after the 2004 Madrid train bombings that killed 193 people – it has now emerged he was an informant for Spain’s National Intelligence Center (CNI) during his time in a Castellón prison where he served four years for drug trafficking.