PV,
I'm going to put my two cents in and expound on what Bob3 told you. Looking back on how I got my creds is not the way to go. Though I am a career LEO, and a veteran of many homicides, suicides, and the like dealing with evidence, crime scenes, and deceased persons, OJT is the way I got a lot of my training, and that's a dangerous and poor way to learn. The investigative experience you gain from this is invaluable if you plan to do any underwater crime scene investigation. However, there are MANY functions a PSD can perform without having to be underwater crime scene certified and all the other fancy titles.
You need to do some soul searching and ask yourself why you want to do body recovery and the like. There are many before you with big, expensive sport diving titles that thought they did to until push came to shove. Ask yourself if you can dive for a neighbor whom you've stood on your front porch for years and talked to, whose family members have worked for you, then ask yourself if you can dive for the small children that were killed either by murder or manslaughter, after the turtles and alligators have nibbled on them. And if you still want to do it, start visiting the PSD websites like SMART Divers right there in Texas and the like, and take the opportunity to train and listen to old experienced PSDers before you. You'll be glad you did. Hope this helps. Good luck and dive safe.