Updated

A French ex-intelligence chief is expected to addresses failures in tracking Islamic extremists, at the trial over deadly 2012 attacks on a Jewish school and French soldiers.

Bernard Squarcini was heading the French police counterterrorism agency when Mohamed Merah went on a shooting rampage, killing three French paratroopers, three Jewish schoolchildren and a rabbi.

Squarcini said at the time that Merah acted as a lone wolf and wasn't affiliated with an extremist network. But Merah had been placed on the "fiche S" listing, a register of people suspected of being radicalized, as soon as 2006 because of his relationship with older brother Abdelkader Merah, who is on trial for complicity to terror in connection with the three shooting attacks Mohamed Merah carried out in and near Toulouse.