I have never hire a person to undertake investigations and I haven't had any experiences with them.
I think it would be useful to make sure nobody comes to harm you, when you need to search out evidences of illegal conductes or "bad behaviours".
I wouldn't like to do this job. Although I'm detailed or careful doing things, I'm not intuitive. I must understanding and reasoning about something in order to take an action or decision.
I'm good at solving problems in an inventive way, but I'm a disaster when I work under pressure.
Finally, I hate to overstep the privacy of others as I dislike others invade mine. I'm unable to hurt another, even though they deserve.
I've been consumer safety inspector during five years. I conduct regulatory oversight activities inside suppliers, shops or products.