Police inquiries into three attacks on the Algerian-born former dean of a leading French business school are said to be focusing on professional jealousy, or personal, political or racist motives. A bomb that exploded at Audencia - the second of three attacks - was apparently directed at Aissa Dermouche. A week earlier, his car was blown up and a small explosion ripped apart the letter box of the school attended by his son. No one was injured in the attacks.