These days most Police and Fire Departments have their own dive teams on staff or available. If your local departments do not, the first thing you'd want to do is contact them and ask what requirments they may need.
At the very least, I'd assume you'd need to be a Professional Level diver (Divemaster or above) and carry your own liability insurance that can be obtained through your training agency. The local municipality may also require some sort of advance First Aid/CPR beyond that of the basic level you are required to hold as a Divemaster or above, and finally, some advanced work in rescue and search and recovery. You must keep in mind that often, the type of search and recovery required by a Police Dept. might be far more involved than just locating an item and bringing it to the surface as protecting the integrity of evidence could be vital in solving a crime.
Edited by BobG (07/30/08 12:06 PM)