What are you really trying to accomplish. I think preventive measures would be great for starters. If you set someone up, that would be fun, but you create a liability for you company in regards to your policy and procedures. If you send out a memo, and follow up with security cameras or random checks. I`m a Private Investigator and do a lot of Security Consulting for business and personal. Ipswerks.com. You should consider this before you accuse someone of a crime. That could be more costly then a civil suite.
Not sure if this helps you, but, this is a true and funny story.
A couple my friends worked as custodians for a gym (run by a service organization). They noticed, after hiring a certain employee, that tools were turning up missing.
You didn`t really need to call in CSI for this one.
After a power saw disappeared, they grabbed the employee and showed him a stack--and I mean a stack--of wood that need to be cut to certain dimensions... with a lowly, elbow-greased-powered hand saw. He spent the rest of the day on the project.
The next day, the employee turned up with--wonders of wonders--a saw of the exact make, model, and color as the one that was missing.
Though, the employee was quick to point out that this one had his initials on it (and sure enough his initials were carved into the handle), so it couldn`t possibly be the missing one.
My friends said no more tools disappeared after this.
there are many ways to approach this, currently working in an office supplies retail business, my employer makes a big deal about ethics and trying to create a culture which would reduce this problem.
I personally don`t think it can be eliminated with businesses of a larger size.