I own a Panasonic PV-GS31 Mini DV Digital Camcorder, I am a Private Investigator and while recording the sound needs to be muted, how can I accomplish this?

Hi There, There is no external mic input on that model camera. The only way to do it is you will have to take the front panel off the unit and disconnect the flat mic/audio cable from the front panel. If you do this, tape up the connector so it won't short out the unit. If you had external mic in, you could put a dummy plug in and that would cut the sound from the internal microphone.
Thanks, me cicmo