Russian President Vladimir Putin has promised a group of mothers who lost children in the Beslan school siege one year ago a thorough investigation to establish whether official incompetence contributed to the deaths of 331 hostages. Thirty mothers from the southern Russian town met President Putin on Friday. The members of the Beslan Mothers' Committee have accused authorities of covering up and hampering investigations into who started the bloodshed. On Thursday residents in Beslan started three days of mourning to remember those killed after Russian troops stormed a school where suspected Chechen rebels had taken over 1,000 people hostage. Most of the dead were children.