It was harmless error for the trial court to allow the bailiff, outside defendant’s presence, to demonstrate the operation of the murder weapon and to answer jury questions regarding the weapon. Johnson, a CHP officer, was convicted by jury of the first degree murder of her husband. On appeal Johnson claimed her right to be present during trial was violated when the trial court, outside her presence, allowed the bailiff to demonstrate the operation of the murder weapon (a gun) to the jury and answer questions regarding the weapon. Held: Affirmed. The federal and state Constitutions and Penal Code sections 977 and 1043 guarantee a defendant’s right to be present at a critical stage of the proceedings. Here, the deliberating jury requested a readback of defendant’s testimony about how the gun was discharged and a demonstration of the gun. Defense counsel waived defendant’s presence. Without defendant present, the bailiff conducted a demonstration and spoke to the jury about the gun’s operation in open court, responding to a number of questions. The demonstration was essentially testimony and amounted to the jury’s receipt of evidence. As a result, it was a critical stage of defendant’s trial and the trial court erred by allowing the demonstration without defendant’s presence. Counsel’s waiver of defendant’s presence was ineffective because a written waiver executed by the defendant was required for her absence at a hearing where evidence was taken. Further, there was nothing in the record that reflected defendant knew there would be a demonstration or that the bailiff would answer questions. However, the error was harmless beyond a reasonable doubt because the bailiff’s demonstration and responses were materially the same as the testimony of the prosecution’s gun expert. Although the prosecution’s forensic evidence contradicted appellant’s testimony that the gun fired accidentally, she did not challenge his opinion during her testimony and did not offer her own expert testimony.