The judge questions witnesses, interrogates suspects, and orders searches for other investigations. Their role is not to prosecute the accused, but to gather facts, and as such their duty is to look for any and all evidence, whether incriminating or exculpatory ("à charge et à décharge"). Both the prosecution and the defense may request the judge to act, and may appeal the judge's decisions before an appellate court. The scope of the inquiry is limited by the mandate given by the prosecutor's office: the examining judge cannot open a criminal investigation "sua sponte."