Protecting Server Content?

[Joshua_P2P]

So recently i hired a staff member (not mentioning names) but the staff member was at the rank of a scripter. This individual had added multiple things to my server which i had yet to see anywhere else so i had assumed he made this content. Later after working there for a while he requested access to view a script (A Inventory script and class) saying he wanted to "learn" from it. Not knowing there were other intentions i gave him access thinking if he's contributed this much to my server i might as well help him with his scripting abilities and allow him to view the script.

So a week goes by and a server admin and I are working on my server. He was looking through all the scripts to see what we needed and what needed to be worked on. He looked at the Inventory and added it to himself to see what it looked like in client. He then proceeded to tell me how it looked nice but he's seen it on other servers. Not knowing what was going on i visited 3 servers with the same Inventory system as me just modified a bit in size and a button added to make it look a little different however it was the same. I suppose mentioning the name does no harm, my server admin is AlexDamian. After looking through several servers with the same inventory i asked Alex if he could contact Carlito regarding the matter and what actions could be taken to remove the content from my server on others. From my understanding Carlito told Alex there isn't sufficient proof to remove the content or to say those servers didn't create it themselves. The Question i bring before the community today is how am i supposed to protect my server content and prove that it is mine? Obviously if someone stole something they aren't going to admit to doing it so what other options do i have to prevent this from happening in the future? Content can easily be modified by changing text in a script or rearranging tiles in a level to make it look like it's original when it isn't. So aside from giving staff personal rights (which i already do) what other steps can be taken that in the event content is stolen, i can prove it's mine?