Witnesses may be examined regarding any matter, not privileged, which is relevant to the subject matter involved in the pending contested election case, whether it relates to the claim or defense of the examining party or the claim or defense of the opposing party, including the existence, description, nature, custody, condition and location of any books, papers, documents, or other tangible things and the identity and location of persons having knowledge of relevant facts. After the examining party has examined the witness the opposing party may cross examine.