Complex sentence: He was listed by Russia as one of the killed suspects of the 2004 Beslan school siege, as the person who led the negotiations on behalf of the hostage takers under the name Ali whose body was identified after he was killed during the storming of the school.
Split into simpler sentences: He was listed by Russia as one of the killed suspects of the 2004 Beslan school siege, as the person who led the negotiations on behalf of the hostage takers under the name Ali. Documents alleged his body was identified after he was killed during the storming of the school.