An unfortunately common misconception that is rife among laypeople who do not know all that much about the world is that PIs, which is short for private investigators, are able to do anything that they would like to do to finish the job. In spite of the fact that this is the case, it is important to note that a lot of private investigators go beyond the boundaries of the law, and that is something that is making the world a much worse place than it already is at the end of the day.
In the even that you suspect that someone from a private detective agency is following you, you should get some advice from true professionals who would never break the law like www.mydenverpi.com. The biggest piece of advice that they would be willing to send your way would be that you should report this to the officials. Police officers are often aware of what PIs are operating in what areas, and suffice it to say that if a private investigator is crossing any and all boundaries while they are chasing after you they will have to face the full brunt of the law that they are so eagerly trying to play with.
Illegal surveillance is a major crime, and the PI would only ever be let off the hook if they prove that you were committing a crime. Protecting yourself from rogue PIs is something that you should take very seriously indeed because you never know when one of them might make it their mission to cause problems for you despite you being the truest example of a model citizen all in all.