Nice attacker: Terrorist or 'simply deranged'?

A clearer picture is emerging of the man behind the Nice attack - a drug user who picked up men and women using dating sites. Bouhlel is thought to have become radicalised "very quickly"; but to what extent was Islamic fundamentalism an excuse for a pre-existing violent streak? Several media examine the increasingly blurry line between a terrorist and someone who is "simply deranged".