The article is in error. The two graves weren’t 70 km apart; I think the correct distance is 70 meters.
I wondered why captors would risk removing the Czar’s children (one of whom would be the heir to the monarchy) so far from their place of imprisonment, just to execute them.
In any case, I thought it was horrific that children would be murdered at all ...never mind that they would have to spend their last moments on earth away from their parents and to die so brutally and alone! Ghastly.