A Russian man went on trial Wednesday over the assassination of a former Chechen commander in a Berlin park, allegedly on Moscow's orders, a case that risks worsening acrimonious ties between Germany and Russia. Vadim K., also known as Vadim S., stands accused of gunning down a Georgian national identified by German authorities as 40-year-old Tornike K., in Kleiner Tiergarten park on August 23 last year. Prosecutors believe that Russia ordered the killing. ilp-hmn/dlc/jj