If possible, gain a working relationship with police in your community. Many police officers have little use for PIs, but if you know the law, behave in a professional manner, and are diligent in solving cases, they'll often accept you as a professional. Never get between officers or special agents and their work. Never try to take over a case or crime scene, even though you've been hired to work the case.

Know your position and work within it. Be respectful of the officer's time and expertise, and offer to help where you can. Be willing to do the grunt work. Should you arrive on a scene where a car needs to be pushed off the road, join in with the pushing. If the officer gives you a direct order, don't push it. Even PIs who are former or retired law enforcement officers are subject to obeying commissioned officers, so don't feel rained on if you're asked to step aside, and don't make a scene. Acting out is the best way to burn your bridges with these officers and others.

Letting maltreatment roll off your back and treating those who are rude with respect can sometimes put a mirror in front of the face of the person acting badly. You may have caught him on a bad day. There may have been a tragedy in his family or circle of friends. You never know why someone reacts with venom for no apparent reason. Try returning kindness for bad treatment. Turning the other cheek isn't just a platitude; it often really works to defuse unreasonable anger. By giving Mr. Rude the benefit of the doubt, you may turn him into a friend. However, if he doesn't come around, this says something about him, not you, so let it go. Realize that he won't be one of your contacts, and good riddance.