KYIV (Reuters) – Ukraine’s State Bureau of Investigation has completed a pre-trial investigation into pro-Russian politician Viktor Medvedchuk, who is accused of treason, and it has filed the case to court, the law enforcement agency said on Thursday. Medvedchuk, one of President Vladimir Putin’s allies in Ukraine, faces up to 15 years in jail if convicted of treason and violating the laws and customs of war, the agency said in a statement on its website. The investigators’ report says Medvedchuk provided the leadership of Russia with assistance in carrying out subversive activities against Uk…