I also agree with Gary, they are a useful tool.The only experience I had was on a drowning 2 yrs. ago out of state that our team was called in to assist with. It was above a Dam with a current,victim was dressed only in underwear.
The Cadaver dogs kept hitting in a particular area approx. 60ft. deep, we started to search the area and found a huge tree pile underwater, we began the tedious task of searching it but, weather conditions changed for the worse and the onsite commander pulled the teams.
The body surfaced the next morning, I believe the dogs put us on the right area though and had we been able too continue the search we would of been successful with their help.