As the office manager, I would approach the situation with my administrative assistant in a professional and non-accusatory manner. I would start by scheduling a private meeting with the assistant to discuss the issue. During the meeting, I would say something along these lines:
"Hi [Assistant's Name], I noticed that our supply cabinet has been depleted of tape, scissors, and packing materials. Since you and I are the only ones with access to the cabinet, I thought it would be best to discuss this matter openly. I want to understand if there might be any specific reason for the shortage of supplies.
As the administrative assistant, you play a crucial role in managing office supplies, and it's important for us to ensure that they are available when needed for various tasks. I would like to figure out if there's any issue with the supply process or if there's something we can do to prevent such shortages in the future.
If there's anything you'd like to share about the situation or any concerns you have, please feel free to talk about it. Our goal is to maintain a well-organized and efficient office, and your input is valuable in achieving that. Let's work together to find a solution to ensure our supplies are appropriately managed moving forward."
This approach shows understanding while addressing the concern and encourages open communication to resolve the issue collaboratively. It's essential not to jump to conclusions or make accusations without first discussing the matter with the administrative assistant. There could be valid reasons for the supply depletion, and this conversation aims to explore those reasons and find a solution together.