WordWeb Online

1. Marked by inquisitive interest; especially suggestive of an ecclesiastical inquisitor
   "the press was inquisitorial to the point of antagonism"; "a practical police force with true inquisitorial talents"
    
2. Having the authority to conduct official investigations
   "the inquisitorial power of the Senate"
    
3. Especially indicating a form of prosecution in which proceedings are secret and the accused is questioned by a prosecutor who acts also as the judge

See also: inquiring

Antonym: accusatorial

Encyclopedia: Inquisitorial