Mometrix has the best study materials because it contains a step-by-step guide to the areas you’ll likely see on the Private Investigator’s exam. Our study guide reviews dozens of topics including robbery types, crime scene processing, conducting research, reporting writing, body language, presenting cases, presenting testimony, federal rules of evidence, and so much more. Our flashcards help you retain information through repetition, one of the best learning techniques around. These are the two tools you need to help you prepare.