A Russian investigator has said grenades fired by surrounding Russian forces could have triggered the Beslan school bloodbath in September 2004. Yuri Savelyev's conclusions contradict the official view that bombs planted by the hostage-takers in the school gym went off just before the gun battle. Mr Savelyev is a member of the Russian parliamentary commission investigating the siege, in which 331 people died. Many of the victims were children, taken hostage by pro-Chechen militants.