1. When such motion is on notice, a hearing thereon shall be held by the court before which it is returnable not later than thirty days after the return date and the defendant shall be present at such hearing. 2. A hearing held pursuant to this section shall be conducted and recorded in the same manner as would be required were the witnesses testifying at trial. The district attorney shall establish by competent evidence the nature and quantity of the dangerous drugs which are the subject of the motion. Each party shall have the right to call and cross examine witnesses and to register objections and to receive rulings of the court thereon. 3. If the court finds upon the conclusion of the hearing that neither the prosecution nor the defendant will be prejudiced thereby it may grant the motion and may make such order as it may deem appropriate for the destruction of part or all of such drugs. 4. A defendant may waive such hearing and consent to the granting of the motion and entry of an order of destruction either by sworn affidavit or by personal appearance in court and declaration on the record of such waiver and consent.