There are several important things to remember about any private investigator. First of all, they are usually operating on their own. This means that they aren't going to have any bosses that you can go to, or higher up people that you can talk to. For you ,this means that you have to be happy with what they are doing. For them, this means that often times they can do whatever they want. Sometimes, this makes for a situation where you are much more guaranteed to get your information. But, on rare occasions, this can lead to trouble. It is often hard to have a set contract when you are working with a investigator, so often you want to be sure that you have sat down with them and have discussed exactly what you would like them to find out. You also want to be sure that you have discussed various prices and fees at that time.