An independent public commission to investigate the bombings chaired by Duma deputy Sergei Kovalev was hampered by government refusal to respond to its inquiries .
Commission 's chairmen admitted that he has no evidence to support any version of the events .
An independent public commission to investigate the bombings chaired by Duma deputy Sergei Kovalev was hampered by government refusal to respond to its inquiries , and its chairmen admitted that he has no evidence to support any version of the events .