1850's Sheffield plate tea caddy missed!

I went back to the shop after I had eaten dinner this evening and was Shocked to find a circa 1850's Sheffield plate tea caddy missing!  It had been setting on the top of my role top work desk waiting for us to finish our research and price it.  I knew that it had been sitting there earlier in the
day. But, it was not there!  I called my business partner and ask him if he had placed it somewhere else and he said no.
Well, today I had a bit off an altercation with one of our pickers that was being a pest. Wile we were having words outside the shop a person went into the shop that I did not notice, but one of my friends that was present said to me that a customer had entered the shop. I went in and there was this guy and another young guy and girl.  The guy wanted to examine a great number of sterling items. My friend came in and the guy and girl left immediately. The only thing that I could figure out was that the guy and girl had trespassed into our private work area and took the item off my desk and when my friend came in they had chickened out and left not taking the caddy. I later accidentally found the tea caddy hidden in the back area of the shop.
I guess when my friend came in they were afraid they would be caught so they dropped the caddy in the back area of our shop and fled! This time of year this type of thing happens frequently. It would have been very sad if they had taken the tea caddy, but it would have been way sadder if they had taken either of the two items that were setting beside it, because they were not plate, but very rare sterling items! I can only assume that they were not very knowledgeably about silver and only grabbed the caddy because it was large and cool looking.