A BBC report suggests a motive and context for this incident:
Ethiopia's army is trying to rescue 108 women and children abducted in a cross-border raid in the western Gambella region, the government says.
It blamed Friday's raid, in which 208 people died, on the Murle community from neighbouring South Sudan.


The Murle have previously been accused of carrying out cattle raids and stealing children to raise as their own.
Link:http://www.bbc.co.uk/news/world-africa-36071090