Texas Code of Criminal Procedure - CRIM P Art. 20A.257. Examination of Witnesses

(a) Only a grand juror or the attorney representing the state may examine a witness before the grand jury.

(b) The attorney representing the state shall advise the grand jury regarding the proper mode of examining a witness.

(c) If a felony has been committed in any county in the grand jury's jurisdiction, and the name of the offender is known or unknown or if it is uncertain when or how the felony was committed, the grand jury shall first state the subject matter under investigation to a witness called before the grand jury and may then ask questions relevant to the transaction in general terms and in a manner that enables a determination as to whether the witness has knowledge of the violation of any particular law by any person, and if so, by what person.