Investigators face tough task in Ukraine plane inquiry

BERLIN/GENEVA (Reuters) - As international investigators head to rebel-held eastern Ukraine to piece together what - and who - caused a Malaysian airliner to plunge into the steppe, securing evidence in the middle of a war zone is a major challenge.

Proving what happened beyond doubt and to the satisfaction of the warring parties may already be all but impossible, after local people and rebel fighters have spent 24 hours sifting and moving debris and bodies and Ukraine and Russia make detailed allegations against each other and argue over the black boxes.