exculpate       
verb [ T ]  formal uk/ˈek.skəl.peɪt/ us/ˈek.skəl.peɪt/
 为…开脱;证明…无罪
to remove blame from someone
  The pilot of the aircraft will surely be exculpated when all the facts are known. 当一切真相大白时,肯定可以证明飞行员是没有过错的。 
 Synonyms: clear exonerate 
Opposite: convict 
Compare: acquit