Chechen separatist leader Doku Umarov claimed responsibility for the attack which killed 28 and injured countless others when the blast derailed the Nevsky Express luxury train Nov. 28, 2009.
Murat, Tatarkhan and Beslan Kartoyev were sentenced to life in prison along with Umarov Tuesday, RIA Novosti reported.
Six other members of the Kartoyev family were sentenced to shorter prison terms, seven to eight years each.
RIA Novosti reported defense attorneys plan to appeal the decision to the Supreme Court.
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