Recycle Bin on network share empty?

When users who are saving data on server, delete items shouldn’t they go to the recycler on the share? Mine is always empty. If it should be shared, how do I set permissions so they cannot delete what’s in the recycle bin. Example: Have students who are loading hacking software, using, and then deleting. Virus software picks it up, but then I can’t retrieve who it came from. Any ideas on how I can find who this is? Students have used Nuke.fck and port.fck or something similar – Help…..