Office Bullying

Have you ever had an issue of office bullying? If somebody was receiving malicious calls from either internal or external sources, would you be able to identify the culprit?
 
By running detailed Call Logging Reports, you can see all calls to an extension. You could then narrow down whether the call was internal or external. If internal, you could set-up a real-time screen which alerts you as soon as that number is dialled, you can then check to see who was using that extension at that time.