The arrest of an Islamist in Morocco has made Belgian authorities wondering if they have been duped by a “double agent” alleged to have acted as an informer while planning several deadly attacks. The growing storm is swirling around Abdelkader Belliraj, 50, a Belgian and Moroccan national who was arrested last month in Morocco on suspicions of having led an Al Qaeda-linked group of 35 Islamic extremists. He is also a prime suspect in six unexplained killings in Belgium at the end of the 1980s, including the murder of Joseph Wybran, a former head of the umbrella group of Belgian Jewish organizations. Although the Moroccan accusations were at first met with scepticism in Belgium, authorities now consider them credible. It appears now, as details emerge, that Belliraj was probably for years a paid informer for Belgium’s domestic intelligence services, the State Security. Moroccan authorities say Belliraj has confessed to killing in Belgium, in 1989 alone, the representative of the Jewish community, two moderate Muslim officials and a driver for the Saudi Arabian ambassador mistaken for a diplomat.