The judge, the judge’s delegate, or an auditor examines the witness; the examiner must have the assistance of a notary. Consequently, if the parties, the promoter of justice, the defender of the bond, or the advocates present at the examination have any questions to be put to the witness, they are to propose them not to the witness but to the judge or the one who takes the place of the judge, who is to ask the questions, unless particular law provides otherwise.
Source: Code of Canon Law (Vatican.va)