In July 2007, the Mothers of Beslan asked the FSB to declassify video and audio archives on Beslan, saying there should be no secrets in the investigation. They did not receive any official answer to this request. However, the Mothers received an anonymous video, which they disclosed saying it might prove that the Russian security forces started the massacre by firing rocket-propelled grenades on the besieged building. The film had been kept secret by the authorities for nearly three years before being officially released by the Mothers on 4 September 2007. The graphic film apparently shows the prosecutors and military experts surveying the unexploded shrapnel-based bombs of the militants and structural damage in the school in Beslan shortly after the massacre. Footage shows a large hole in the wall of the sports hall, with a man saying, "The hole in the wall is not from this of explosion. Apparently someone fired adding that many victims bear no sign of shrapnel wounds. In another scene filmed next morning, a uniformed investigator points out that most of the IEDs in the school actually did not go off, and then points out a hole in the floor which he calls a "puncture of an explosive character".