In this situation, calling the police may have been a good idea. However, in some situations it's not always the best idea. In fact, it can be a terrible idea. Be aware of unintended consequences of getting the police involved.
For just one example, consider the case of a domestic dispute between you and your spouse or ex. Perhaps your ex shows up and demands something from you, and refuses to leave. Calling the police can certainly get one of you arrested. In many cases, the person making the call will be the one arrested! In many police departments, the police will have to file a report explaining exactly WHY they did not make an arrest. Often they feel they HAVE to arrest someone. It may even be a rule, written or not.
Get a domestic violence conviction and kiss your guns goodbye.
If you doubt this, do a little research, or talk to some cops. Here are two links: