Source : Webster's Revised Unabridged Dictionary (1913)

Inspector \In*spect"or\, n. [L.: cf. F. inspecteur.]
   One who inspects, views, or oversees; one to whom the
   supervision of any work is committed; one who makes an
   official view or examination, as a military or civil officer;
   a superintendent; a supervisor; an overseer.

   {Inspector general} (Mil.), a staff officer of an army, whose
      duties are those of inspection, and embrace everything
      relative to organization, recruiting, discharge,
      administration, accountability for money and property,
      instruction, police, and discipline.

Source : WordNet®

inspector general
     n : a military officer responsible for investigations