US expert says detention and trial of Ukrainian pilot part of Kremlin revenge
Ukrainian pilot Nadiya Savchenko has been sentenced to 22 years in prison by a Russian court.
Judges found her guilty on charges of complicity in the deaths of two Russian journalists and of crossing the Russian border illegally.
Read also Savchenko Trial Verdict (updates)
For the duration of her case her legal team have said the charges are fabricated and a guilty verdict was a foregone conclusion.
Georgetown University Professor Phillip Karber suggests one possible explanation for why Russian President Vladimir Putin is refusing to release her.