Auditing of Users

I have an NT server right now, I need to find a way to audit usage on the server- specifically the addition and deletion of files, the names, and sizes of each. Example-someone had a folder deleted but didn’t delete it themselves, I’d like to go and find out ‘who’ actually deleted it. The auditing options doesn’t really seem to get that specific—I have an event log archiver and analyser, but the actual audit needs to be there…..does anyone know how to get that specific on NT or know of any cheap 3rd party software that manages such information?
thanks in advance