Facing any kind of legal action for something that you had nothing at all to do with would obviously not be an ideal circumstance for you to find yourself in at any given point in time. Trying to avoid such legal calamities is likely a top priority for you in some way, shape or form, and there are several ways in which you can go about predicting what the future brings with being on the lookout for private investigators being prime among them.
A big part of the reason why that is the case has to do with the fact that anyone that wants to try to do you any legal harm would first hire someone from a private detective firm, and suffice it to say that most firms are not going to nearly as ethical as mydenverpi. Hence, if you notice that there is someone that has been around you a little too frequently for you to be comfortable about it, the only possible thing for you to do in response would be to call the police and tell them that someone near you is making you fear for your safety.
This will result in the police sweeping in and taking the PI away from you for the foreseeable future. The next step would be to call your lawyer of course, and chances are that this lawyer will send their own PI out to figure out who hired the one that was sent to tail you. You need to be able to protect yourself and this may very well be the single best way for you to end up doing so to a reasonable extent.